PROCEEDINGS     OF     CONFERENCE 
OF   MEN  ENGAGED 


IN 


GRAIN  DUST  EXPLOSION 

AND    FIRE    PREVENTION 

CAMPAIGN 


CONDUCTED  BY 


United  States  Grain  Corporation 


IN  COOPERATION  WITH 


BUREAU  OF  CHEMISTRY 

United  States  Department  of  Agriculture 


42  BROADWAY,  NEW  YORK,  \.   V. 
APRIL  22-24,  1920 


M  w     YORK 
JULY,  1920 


CONTENTS 


OPENING  SESSION,  THURSDAY  AFTERNOON,  APRIL  22,  1920. 
D.  J.   Price,   Presiding 

PAGE 

Possible  Lines  of  Extension  of  Dust  Explosion  Work  in  Commer- 
cial Fields,  by  H.  R.  Brown 3-11 

Changes  in  Elevator  Construction  Suggested  by  Recent  Explosions, 

by  J.  O.  Reed 11-27 

Latest  Developments  and  Devices  for  Prevention  of  Chokes  in 
Elevator  Legs,  by  P.  E.  Brady 27-33 

A  Discussion  of  the  Relation  of  Grain  Dust  Explosions  as  Ap- 
plied to  Flat-Warehouses  and  Elevators,  by  G.  P.  Bodnar 34-37 

Experiences  That  Have  Been  Helpful  in  Making  Inspections,  by 

G.  A.  Hibbard 37-42 

FRIDAY   MORNING   SESSION,  APRIL  23,   1920. 
Dr.  J.  W.  T.  Duvel,   Presiding 

Static  Electricity  in  Attrition  Mills  and  Methods  of  Removal,  by 
M.  E.  McCollam 42-46 

Recent  Investigations  of  Static  Conditions  in  Industrial  Plants, 
by  H.  K.   Roethe 47-59 

Relation   of    Electrical   Equipment   to   Dust   Explosions,   by   D.   J. 

I  Vice    60-66 

Special  Features  in  Lighting,  by  E.  I'».  Fox,  Commercial  Engineer, 

Edison    I. amp   Company 66-74 

entation  of  Dust  Explosion  Work  Before  High  School  Stu- 
dents, by  E.  L.  Riley 74-77 

FRIDAY   AFTERNOON    SESSION,   APRIL  23,   1920. 
1  )k.  II.  11.  Brow \,  Presiding. 
Results  of   Work   in   Various   Districts — 

Review  ol  Work  in  Eastern  District,  bj  H.  R.  Brown 

Review   ol   Work  in  Central  and   Northwestern   Districts,  by 

1'.   E.   Bradj 

Review  of  Work  in  Pacific  District,  by  M    E    \i.  I  ollam 

ission  of  Experience  in  Making  Inspections 

kt  \  lew  oi  Explosions  I  >ui  i  

Kansas  City  Explosion,  by   I    0.  Reed 

Effecl   "i   the   Kansas   Citj    Explosion  on   Inspection   Work 
in  the  Southwest,  by  1 1.  J.  Helrnkamp. . 


PAGE 

Review  of   Explosions   During  Past   Year — Continued — 

Port  Colborne  Explosion,  by  Dr.  H.  H.  Brown 100-104 

Denver,   Colorado,   Explosion,  by  D.  J.   Price 104-109 

Explosion,  Aluminum  Goods  Manufacturing  Company,  Mani- 
towoc, Wisconsin,  by  P.  E.  Brady 110-116 

Explosion  in  Feed  Mill  and  Elevator,  Buffalo.  New  York,  by 

H.  J.  Helmkamp 116-119 

"H-O"  Mill  Explosion  at  Buffalo,  New  York.  In    K.  L.  Riley. .     119-120 
Newton   Tea   &    Spice    Company    Fire,    Cincinnati,    Ohio,    by 

E.  L.  Riley 120-121 

Statement  by  Julius  H.  Barnes,  U.  S.  Wheat  Director,  and  Presi- 
dent of  U.  S.  Grain  Corporation 98 

Statement  by  Dr.  C.  L.  Alsberg,  Chief,  Bureau  of  Chemistry,  U.  S. 

Department  of  Agriculture 98-100 


SATURDAY  MORNING  SESSION,  APRIL  24.   1920. 
E.  N.  Bates,   Presiding. 

Suction  vs.  Bucket  Elevating  in  Handling  of  Grain,  by  G.  D. 
Witmer   122-127 

Relation  of  Aspirating  Systems  in  Grain  Elevators  to  Dust  Ex- 
plosions, by  W.  B.  Lind 127-153 

A  System  of  Air  Purification  in  Flour  Mills,  by  H.  J.  Helmkamp.     133-138 

Results  and  Impressions  in  Dust  Explosion  Meetings,  by  Dr.  H.  H. 
Brown   138-145 

Statement  by  Watson  S.  Moore.  Director  and  Second  Vice-Presi- 
dent, U.  S.  Grain  Corporation 145-147 

Interest  of  Grain  Corporation   in   Dust    Explosion    Prevention,  by 

Dr.  J.  W.  T.  Duvel 148-151 

Summary  of  Dust   Explosion  and  Fire   Prevention  Campaign,  by 

D.  J.  Price 151-15') 


PROCEEDINGS  OF   CONFERENCE  OF  MEN  ENGAGED 

IN  GRAIN  DUST  EXPLOSION  AND  FIRE 

PREVENTION  CAMPAIGN 

Conducted    by 

UNITED   STATES   GRAIN   CORPORATION 

In    Cooperation    with 

Bureau    of  Chemistry,  U.  S.  Department  of    Agriculture 

42  Broadway,  New  York,  N.    Y. 

April  22-24,  1920 


NAMES  AND  ADDRESSES  OF  THOSE  PRESENT  AT  CON- 
FERENCE. 

Alsberg,    Dr.   C.   L.,   Chief,   Bureau   of   Chemistry,    U.    S.    Department   of 

Agriculture,   Washington.   J).   C. 
Bailey.   Dr.  ( '.   II..   University  of    Minnesota,   St.   Faul,  Minnesota. 
Barnes,  J.  II  .   United  States  Wheat  Director,  and  President,  U.  S.  Grain 

Corporation,  42  Broadway,  New  York.  N.   Y. 
Bates,    K.    N.,    Investigator,   Bureau   of   Markets,   U.    S.    Department   of 

Agriculture,  Washington,   D.  C. 
Bodnar,  G.  P.,  In  Charge  of  Grain  Dust  Explosion  Prevention  Campaign 

at  Portland,  Oregon. 
Boerner,  E.  G.,  In  Charge  Grain  Investigations,  Bureau  of  Market-.  U.  S. 

Department  of  Agriculture,  Washington,   D.  C. 
Brady,  P.  E.f  In  (harm-  of  Northwestern  District,  U.  S.  Grain  I  i 

don,  Minneapolis,  Minnesota. 
Brown,  Dr.  H.  H.,  Organic  and  Physical  Chemist,  Bureau  of  Chemistry, 

U.  S.  Department  of  Agriculture,  Washington,  D.  C. 
Brown,  11.  R.,  In  Charge,  Eastern  District,  Bureau  <>i  Chemistry,   U    S 

Department  of  Agriculture,  Washington,  I1 
Dedrick,   B.  W.,  Instructor  in  Milling  Engineering,  State  College,  Peiuv 

s\  K  ania. 

Duvel,  Dr.   I.  W.  T.,  In  Charge,  Grain  Dust   Explosion   Preventioi 

paign,  U.  S.  Gram  Corporation,  New  York,  N.  V 
Fox,   E.   B.,  Commercial   Engineering   Department,   Edison   Lamp   Work-. 

Harrison,  New   Jersey. 
Fritz,  C.   M-.   Federal  Grain  Supervisor,   Bureau  of   Markets,   I      S    Dc 

partment  of    Agriculture,  (  hicago,  Illinois, 
rlelmkamp,  II.  J  ,   In  I  harge  o\  Grain   Dust   Explosion  Preventioi 

paign  at    Kansas  (  it> .   M  issoui  i. 
riibbard,  G.   A.,   In  Chai  Irain   Dust    Explosion    Prevention 

paign  at  t  hicago,   I  llinois. 


Lind,  W.  B.,  Assistant,  Grain  Dust  Explosion  Prevention  Campaign, 
Minneapolis,  Minnesota. 

McCollam,  M.  E.,  In  Charge,  Pacific  District,  U.  S.  Grain  Corporation, 
San  Francisco,  California. 

Moore,  \V.  S.,  Director  and  Second  Vice-President,  U.  S.  Grain  Corpora- 
tion, 42  Broadway,  New  York,  N.  Y. 

Price,  D.  J.,  Engineer  in  Charge,  Grain  Dust  Explosion  Investigations, 
Bureau  of  Chemistry,  U.  S.  Department  of  Agriculture,  Wash- 
ington, D.  C. 

Reed,  J.  O.,  Assistant,  Grain  Dust  Explosion  Prevention  Campaign,  Bu- 
reau of  Chemistry,  U.  S.  Department  of  Agriculture,  Washington, 
D.  C. 

Riley,  E.  L.,  In  Charge  of  Grain  Dust  Explosion  Prevention  Campaign 
at  Buffalo,  New  York 

Roethe,  H.  E.,  Assistant,  Grain  Dust  Explosion  Prevention  Campaign, 
Bureau  of  Chemistry,  U.  S.  Department  of  Agriculture,  Washing- 
ton, D.  C. 

Waters,  J.  P.,  New  York,  N.  Y. 

Witmer,  G.  D.,  Assistant,  Grain  Dust  Explosion  Prevention  Campaign, 
Bureau  of  Chemistry,  U.  S.  Department  of  Agriculture,  Washing- 
ton, D.  C. 


Stenographic  Record  by 

Ratlin n  M.  Orr,   Bureau  of  Chemistry,  Washington,  D.  C. 
Hilda  A.  Sternburgh,  U.  S.  Grain  Corporation,  New  York,  N.  Y. 


OPENING  SESSION,  THURSDAY  AFTERNOON 

April  22,  1920 
D.  J.  PRICE,  PRESIDING 

Mr.  PRICE — The  dust  explosion  prevention  campaign  initi- 
ated by  the  U.  S.  Department  of  Agriculture  in  October,  1917, 
has  been  continued  by  the  U.  S.  Grain  Corporation  since  July 
1,  1919.  This  conference  of  field  men  engaged  in  this  work  has 
been  called  to  consider  and  discuss  certain  important  phases 
of  dust  explosion  and  fire  prevention  work  that  have  developed 
during  the  progress  of  the  campaign.  In  addition  to  the  men 
who  are  actually  engaged  in  this  work,  we  have  in  attendance 
others  who  have  been  interested  in  it-  conduct.  We  are  glad  to 
welcome  them  and  invite  them  to  assist  in  the  consideration  of  the 
various  subjects. 

The  conference  will  be  somewhat  similar  to  the  one  held  a 
year  ago  in  Chicago  in  connection  with  the  war  emergency  cam- 
paign. The  program  as  outlined  will  include  the  more  important 
development-  pertaining  to  this  work. 

In  addition  to  the  subjects  listed  in  our  program,  we  are  to 
have  the  honor  of  having  Mr.  Barnes,  President  of  the  I' 
Grain  Corporation,  and  Dr.  Alsberg,  Chief  of  the  Bureau  of 
Chemistry,  address  us  sometime  during  the  afternoon  session 
on  Friday.  Mr.  Moore,  \  ice  Presidenl  of  the  U.  S.  Grain  Cor- 
poration, has  also  very  kindly  consented  to  address  us  on  Satur- 
day morning. 

The  first  subject  presented  will  be  "Possible  Lines  of  Exten- 
sion of  Dust  Explosion  Work  in  Commercial  Fields,"  by  II.  R. 
Brown,  in  charge  of  the  work  in  the  Eastern  District. 

"p  >SSIBLE  LINES  '  >F  I  A  I  ENSN  >X  I  >K  DCS  I    EXP1  i  • 
Sl<  ).\  \Y<  )KK   IX  D  >MMER<  I  \l.  FIELDS  " 

By  1 1\  i  h»\  l\.  Brow  \ 

'I  his  is  certainh  a  broad  subject  hut  I  believe  it  covers  the 
keynote  of  the  entire  conference,  thai  is:  "How  can  the  dust 
explosion  work  be  continued  "'  or  rather,  "How  can  the  results 
of  our  investigations  !»•  put  <»n  a  practical  working  basis?" 


Now  we  must  admit  that  at  present  there  are  no  funds  avail- 
able to  continue  the  work  in  its  present  form  after  July  1.  That 
does  not  mean  that  the  work  is  finished  but  rather  that  it  has 
been  divided  into  a  number  of  smaller  working  units.  As  we 
go  out  into  other  fields  we  are  going  to  carry  the  dust  explosion 
work  with  us.  Some  of  us  will  go  with  milling  or  grain  com- 
panies, others  with  insurance  companies  or  various  kinds  of 
manufacturing  concerns.  ^Yherever  we  go  we  can  carry  the 
story  of  dust  explosion  prevention  and  do  our  bit  to  keep  the 
good  work  moving. 


Dual    Explosion    Demonstration     produced   by  blowing   dual    into  an   open   flame   in   a 

miniature  elevator. 


I   would  like  to  suggest  a  few  methods  which  might  be  fol 
lowed  to  accomplish  this.     If  we  cannot  do  the  work  ourselves 
we  must  ask  other  organizations  to  take  it  up.      For  our  general 
inspection  work  in  its  present  form  the  best  results  can  probably 

he    obtained    through    three    organizations,    namely,    tire    depart 

ments,  Insurance  companies  and  industrial  commissions..     I  hese 
organizations  can   insist   on   the  plants   in   their  districts  being 

clean.    You  remember  our  motto:  "Past  free  nulls  and  elevators 


are  explosion  proof/'  Can  we  not  impress  this  on  these  or- 
ganizations in  such  a  manner  that  they  will  take  up  this  phase  of 
the  work  and  see  that  the  plants  in  their  districts  are  properly 
protected?  Whenever  you  have  an  opportunity  to  present  our 
work  before  any  of  these  organizations  do  so-  The  cheese-cloth 
method  of  demonstrating  is  very  effective  and  easy  to  give. 
When  an  actual  explosion  is  desired  a  packing  case  or  heavy  card- 
board carton  can  be  used  in  place  of  the  miniature  elevator. 

At  one  place  in  the  eastern  district  an  explosion  demonstra- 
tion was  desired  and  we  did  not  have  the  miniature  elevator 
with  us.  A  cardboard  carton  was  obtained,  an  8-inch  piece  of 
pipe  partially  filled  with  starch  inserted  through  a  hole  in  one 
end,  a  flame  placed  within  the  box  and  the  cover  closed.  The 
dust  was  blown  into  the  box  from  the  pipe  and  the  explosion 
which  followed  was  all  that  could  be  desired.  By  giving  demon- 
strations of  this  kind  to  interested  organizations  and  urging  them 
to  do  all  in  their  power  to  protect  the  property  in  which  they 
are  interested  the  good  work  can  be  continued.  All  this  can  be 
done  without  interfering  with  your  other  work  and  I  know 
everyone  will  be  willing  to  take  a  few  minutes  of  their  spare 
time  to  keep  the  dust  explosion  prevention  work  alive. 

During  our  conference  a  number  of  suggestions  will  be  made 
regarding  changes  in  elevator  construction,  changes  in  equip- 
ment, and  methods  of  eliminating  dangerous  conditions.  These 
suggestion-  -In mid  be  given  to  the  mill  and  elevator  construction 
companies  so  that  they  can  make  further  tests  and  determine 
the  most  satisfactory  method  to  adopt.  The  effectiveness  of  the 
revolving  damper,  vrnt  pipe,  and  choke  conveyor  underneath 
attrition  mills,  should  be  brought  to  the  attention  of  machinery 
manufacturers  with  the  purpose  of  having  them  standardize  this 
equipment  and  supply  it  with  their  mills.  Can  we  not  impress 
this  matter  on  the  manufacturers  so  that  new  installations  will 
be  arranged  to  reduce  the  dust  explosion  hazard  in  this  equip 
ment  to  the  minimum? 

The    electrical    companies    have    been    doing     some    excellent 

work  along  the  line  of  dust  explosion  prevention.     When  ex 
plosions  due  to  electrical  equipment  were  reported  they  imme- 
diately started  tests  to  determine  to  what  extent  such  equipment 
might   be  responsible   for  the  starting  of  an  explosion.     Their 
investigations  have  shown  beyond  a  doubt  that  an  explosion  can 

he  started  by   the  breaking  of  an   electric  lamp  in  a   dust)    atmo 

sphere.  Further  tests  are  being  made  by  these  companies  to 
determine  the  best  method  of  protecting  these  lamps  from  break 


age.  In  fact,  a  complete  study  is  being  made  of  the  lighting 
system  used  in  mills  and  elevators.  This  is  a  form  of  co- 
operation which  amounts  to  something.  These  companies  are 
much  better  equipped  than  we  are  to  carry  on  investigational 
work  of  this  kind  and  their  co-operation  represents  the  first  step 
in  the  extension  of  dust  explosion  work  in  commercial  fields. 
The  results  of  their  investigations  can  be  taken  to  the  mills  and 
elevators  in  the  form  of  better  and  safer  lighting  equipment. 

Can  we  not  arrange  other  co-operative  work  with  various 
commercial  concerns?  We  have  started  the  ball  rolling.  Why 
not  have  machinery  companies,  mill  builders  and  dust  collector 
manufacturers  take  up  the  work  and  complete  the  investigations 
which  we  have  started? 

The  Public  Health  Service  should  also  co-operate  with  us  in 
eliminating  the  dust  condition  in  mills  and  elevators.  In  a  num- 
ber of  plants  the  dust  is  so  thick  that  it  menaces  the  health  of 
the  employees,  yet  the  company  is  not  allowed  to  install  a  dust- 
collecting  system  because  it  might  cause  a  difference  of  a  few 
pounds  between  the  incoming  and  the  outgoing  weights  of  the 
grain  handled.  Cannot  the  Public  Health  Service  insist  that  the 
health  of  the  employee  is  worth  more  than  the  slight  loss  in 
the  weight  of  grain,  and  see  that  dust-collecting  systems  are  in- 
stalled? They  would  be  helping  the  employee,  the  company,  and, 
indirectly,  the  dust  explosion  work,  because  dust-free  mills  and 
elevators  are  explosion  proof.  I  would  suggest  that  we  arrange, 
if  possible,  to  have  this  organization  co-operate  with  us. 

Another  method  of  extending  our  work  is  by  using  moving 
pictures  and  magazine  articles  to  bring  the  subject  before  the 
general  public.  I  believe  a  very  interesting  moving  picture  could 
be  prepared  for  public  showing.  Our  present  pictures  are 
adapted  more  for  use  in  lectures  before  technical  societies. 

If  the  magazines  will  publish  an  article  occasionally  on  the 
subject  of  dust  explosions,  or  we  can  have  a  live  story  written 
about  the  work  for  one  of  the  popular  magazines,  the  work  will 
be  kept  before  the  public  and  their  interest  in  the  subject  main 
tained  until   we  are  able  to  put  the  work  on  a  sound  foundation 

and  resume  our  investigations. 

1  have  endeavored  to  make  a  few  suggestions  for  the  ex 
tension  of  the  dnst  explosion  work.  Perhaps  you  have  other 
suggestions  along  this  line-  It  you  have,  I  would  suggest  that 
you  give  them  at  this  time  so  that  we  ran  prepare  a  program  of  co- 
operation and  arrange  for  the  continuation  of  the  work  in  which 
u  c  have  all  become  so  interested. 


Mr.  PRICE — This  subject  was  placed  on  the  program  first 
because  it  was  thought  that  there  have  been  so  many  commercial 
lines  along  which  the  work  might  be  applied,  that  we  could  well 
spend  a  brief  time  in  discussing  some  of  these  phases.  You  re- 
call the  Department  of  Agriculture  discontinued  to  a  large  extent 
the  research  work  relating  to  dust  explosions  and  fires,  at  the 
beginning  of  the  war  emergency  campaign.  Milling  companies 
and  other  industrial  concerns  in  the  meantime  have  taken  up 
parts  of  the  work  of  interest  to  us.  We  will  now  devote  a  brief 
time  to  discussion  and  I  hope  you  will  feel  free  to  respond  with- 
out any  hesitation. 

Dr.  DUVEL — I  am  very  much  interested  in  the  health  ques 
tion  Mr.  Brown  referred  to.  I  would  like  to  know  whether 
you  have  run  across  anything  to  indicate  the  effect  of  dust  in 
mills  and  elevators  on  the  health  of  employees.  Is  it  probable 
that  rye  dust  and  barley  dust  would  be  more  objectionable  than 
dust  from  either  wheat  or  corn  ? 

Mr.  BROWN — I  have  never  run  across  anything  definite 
along  this  line.  Rye,  barley  or  some  form  of  oat  dust  would 
probably  offer  the  greatest  objection  in  the  elevator  line.  I  was 
referring  more  especially  to  the  smut  millers  in  flour  mills.  I 
know  of  two  cases  where  men  engaged  in  this  work  have  had 
to  give  up  the  job.  In  another  case  the  man  seemed  to  enjoy 
very  good  health  and  put  on  weight.  Two  out  of  three  of  the 
men  1  knew  (lid  have  trouble. 

Dr.  DUVEL — You  find  men  complaining  a  great  deal  as  to 
the  had  effects  of  working  in  a  dusty  atmosphere,  y.e1  there  arc 
men  who  have  been  working  under  such  conditions  practically 
all  their  lives  and  >till  apparently  enjoy  good  health. 

Mr.    BR<  >\\'\     Some  claim   it   doesn't   bother  them   in   the 

least,  while  in  some  cases  new  men  go  in  there  and  are  not  able 

t"  -land  it.      1  think  this  question  came  Up  a  year  ago  at  the  Chi- 

-  meeting.  The  question  was  raised  by  Dr.  llnktt  of  Prii 

ton   regarding  the  health  of  people  in    Pittsburgh.     I    recall   it 

Was  shown  at  that  time  that   the  tuberculosis  death   rate  in    Pitts 

burgh  was  lower  than  in  any  other  city,     Whether  smoke  had 

anything  to  do  with  it  or  not  I   don't  know. 

\h    BR(  >\\  X     From  that  side  of  the  question,  a  little  article 
which  came  across  Mr.  Price's  desk  and  mine  yesterday  regard 
ing  a  surve)  which  had  been  made  of  tlie  industries  at   Niagara 
balls,  published  in  a  recent  issue  of  the  St.  Louis  Medical  fournal 


might  be  of  interest.  It  was  found  that  workmen  throughout 
various  types  of  industrial  plants  there  became  diseased  on  ac- 
count of  the  dust,  even  though  apparently  there  was  a  very 
small  amount,  at  least  as  we  see  it  from  the  mill  and  elevator 
standpoint,  in  the  atmosphere.  When  the  dust  was  breathed 
into  the  lungs  it  was  not  given  out,  but  retained  in  the  lungs  and 
eventually  brought  about  congestion  and  disease.  In  thinking 
over  that  side  of  the  question  it  seems  possible  that  when  grain 
dust  is  taken  into  the  lungs  the  starchy  matter  may  be  dissolved, 
being  soluble  in  water,  and  consequently  would  not  have  the 
same  effect  but  we  might  have  that  effect  when  certain  dusts  are 
considered.  Possibly  it  might  be  more  true  in  the  case  of  rice 
dust,  where  the  hull  contains  a  very  high  percentage  of  silicate 
which,  of  course,  is  not  soluble. 

Mr.  McCOLLAM — It  seems  to  me  that  most  everybody  on 
this  inspection  work  should  have  something  to  relate  about  the 
health  of  the  employees  in  the  mills  they  have  visited.  I  remem- 
ber particularly  two  plants,  a  rice  mill  and  a  grain  elevator.  The 
head  miller  in  the  rice  mill  had  a  very  bad  case  of  asthma  which 
he  attributed  to  the  dust  he  had  been  breathing  all  his  life.  The 
man  in  the  grain  elevator  also  had  asthma  which  he  attributed  to 
the  same  cause. 

Mr.  PRICE — The  Public  Health  Service  has  done  quite  a 
little  work  in  some  other  dusty  industries  and  we  hope  this  matter 
may  be  brought  to  their  attention  in  connection  with  our  work- 
in  the  near  future.  In  addition  to  this  phase  that  lias  been  sug- 
gested, there  may  be  some  other  lines  that  might  be  considered. 
We  would  be  glad  to  have  the  same  presented. 

Mr.  BATES — I  should  like  to  ask  you  if  there  is  at  this  time 
an)  plan  relative  to  getting  out  a  publication  regarding  grain 
dusl  explosions  in  mills  and  elevators,  summarizing  and  giving 
results  of  this  work? 

Mr.  PRICE — The  Grain  Corporation  is  planning  that  sort 
of  publication  right  now,  containing  sufficient  information  to 
be  "i  some  value  to  the  industry,  as  more  or  less  of  a  report  of 
what  the  Grain  Corporation  has  been  doing  in  this  campaign 
In  addition,  a  manuscript  is  in  course  of  preparation,  which  is 
almost  ready  to  go  into  publication  channels,  covering  the  work 
from  it-  origin  in  the  Bureau  of  Mines  in  l(U.>  up  to  the  present 
nine     This  i-  a  verj  complete  treatise  of  the  question  as  it  relates 

not    only    to   grain    dusl    DUt    to    other    inllaimnahle    dusts    as    well. 

Both  publications    should  be  available  during  the  present  year  al 

8 


least.     The   Grain   Corporation  publication   will  undoubtedly  be 
ready  soon. 

Dr.  BROWX — It  seems  to  me  that  there  are  some  things  that 
we  ought  to  bring  to  the  attention  of  the  mill  construction  people. 
For  instance,  we  had  a  paper  at  our  conference  last  year  on  the 
question  of  prevention  of  chokes  in  elevator  legs.  We  are  ex- 
pecting to  have  a  further  discussion  of  that  question  at  this  con- 
ference. We  had  a  paper  last  year  on  aspirating  system.-.  We 
are  to  have  a  further  discussion  of  that  this  year.  In  these  and 
in  many  other  cases,  11.  R.  Brown  referred  to  one — the  case  of 
the  revolving  damper,  the  choke  conveyor  and  the  vent  pipe 
being  standardized  by  the  mill  people — it  seem>  to  me  that  these 
and  other  ideas  which  have  been  brought  nut  in  the  development 
of  the  work  should  be  brought  to  the  attention  of  the  mill  con- 
struction people  but  not,  of  course,  given  to  them  as  finished 
products.  We  are  not  able  to  do  that  today.  1  sometimes  doubt 
whether  we  shall  ever  be  able  to  do  that  unless  we  can  get  into  a 
plant  and  develop  these  ideas  on  a  commercial  basis.  These 
people  are  able  to  do  that,  just  as  the  electric  lamp  people  with 
whom  we  are  co-operating  are  able  to  make  direct  tests  and  do 
practical  work.  It  seems  to  me  that  these  ideas  which  we  have 
should  be  given  to  these  companies.  Many  of  us  probably  may 
go  out  into  other  lines  of  work  but  I  don't  think  we  will  ever 
forget  the  associations  we  have  had.  the  ideas  that  have  come 
to  us.  New  ideas  probably  will  develop  from  time  to  time.  We 
will  go  into  other  industries  where  we  may  find  other  informa- 
tion on  dust  collecting  systems  that  we  feel  would  be  more  effi- 
cient in  a  mill  or  elevator  than  any  type  we  have  seen  there,  h 
will  be  worth  while  to  keep  in  mind  that  the  Department  and 
the  trade  is  interested  in  this  problem  and  we  can  send  to  the 
Department  and  through  them  to  the  trade  and  to  the  mill  con 
st ruction  people,  some  of  these  ideas.  For  instance,  I  ran  aero--, 
the  other  day.  a  type  of  what  i-  termed  a  -moke  precipitator 
It  seems  to  me  that  it  i-  something  which  could  be  developed, 
along  a  different  line  possibly,  but  to  be  used  a-  a  -mall  type  of 
dust  precipitator.  The  method  of  operation  was  by  centrifug 
ing,  you  might  say,  the  -moke.  The  -olid  particle-  in  suspension 
were  thrown  to  the  out-ide  and  came  out  a-  a  thick  liquid,  while 

the  air.  freed  from  smoke,  passed  on  <>nt.     It  seems  to  me  that 
this  idea  might  be  developed  in  some  sort  of  way  a-  a  dust  pre 
cipitator,  especially  where  we  have  quantities  of  very  fine  dust 
in  suspension  which  it  doesn't  seem  possible  to  collect  efficiently 
at  the  presenl  time, 


Mr.  PRICE — One  of  the  very  gratifying  things  in  this  work 
is  that  we  have  been  able  in  the  campaign  to  associate  ourselves 
with  some  of  the  most  prominent  milling  and  grain  men  in  the 
country.  We  are  glad  to  have  some  of  those  men  with  us  today. 
Professor  C.  H.  Bailey  of  the  University  of  Minnesota,  St.  Paul, 
came  East  primarily  for  this  conference,  which  indicates  the 
extent  of  his  interest.  He  was  in  charge  of  our  work  for  the 
first  year  in  the  Northwestern  territory.  We  would  like  to  have 
him  discuss  this  paper. 

Dr.  BAILEY — I  don't  know  that  I  have  anything  to  con- 
tribute just  at  this  point.  I  came  to  this  conference  primarily 
to  obtain  rather  than  to  give  information.  These  men  might, 
however,  be  interested  in  the  particular  cause  of  my  attending 
this  conference.  We  are  contemplating  erecting,  this  summer, 
at  Minneapolis,  an  experimental  flour  mill  to  include  a  rather 
elaborate  grain  cleaning  department.  We  want  to  incorporate 
in  that  plant,  as  far  as  our  finances  make  possible,  the  latest  and 
most  useful  of  modern  ideas  with  respect  to  dust-collecting.  I 
have  little  doubt  that  our  grain  cleaning  department  will  be  one 
of  the  most  valuable  parts  of  this  project.  I  will  appreciate  it  if 
you  men  keep  this  matter  in  mind  during  the  course  of  my  stay 
with  you,  that  you  may  give  me  results  of  your  experience  and 
observation  that  will  be  of  use  to  me.  The  plant  which  we  ex- 
pect to  erect  will  not  be  large,  but  we  hope  to  make  it  thoroughly 
modern.  The  mill  is  not  being  erected  by  the  University  or 
Experiment  Station,  but  by  the  State  Railway  and  Warehouse 
Commission.  Our  relations  with  them  are  very  close  and  we 
arc  co-operating  with  them. 

Mr.  PRICE — Professor  Bailey  wants  to  erect  a  dustier  mill 
and  a  dustless  elevator  in  Minneapolis.    He  will  appreciate  the 
ideas  of  you  men.     If  there  isn't  anything   further  on   this  par 
ticular  subject  we  will  take  up  our  next  number  on  the  program. 

At  the  time  of  the  explosion  iii  Kansas  City  last  September 
(when  the  grain  trade  was  wondering  why  this  explosion  occurred 
and  the  circumstances  surrounding  it s  origin)  many  theories  were 
advanced  as  t<»  how  the  explosion  might  have  been  prevented, 
and   numerous   suggestions   made   as   to  how   this  plant   might   be 

rebuilt  to  prevenl  another  explosion   from  occurring.     We.  <>i 

.mi  mu    know,    were    \<t\    directly    Concerned    in   that    e\ 

plosion.     \\C  have  been  longing  for  a  considerable  time  to 
an  actual  explosion  occur-    In  connection  with  our  thresher  work 
m   the   Northwest,  although  approximately   500  explosions  oc- 

10 


curred  in  one  season,  yet  to  my  knowledge  no  man  engaged  in 
the  work  has  actually  seen  an  explosion.  Men  have  reached  the 
scene  soon  after  an  explosion  and  have  left  shortly  he  fore  an 
explosion  occurred.  We  have  also  wished  we  might  be  fortunate 
enough  to  see  a  mill  or  elevator  explosion  without  being  near 
enough  to  be  in  actual  danger.  We  almost  had  that  experience 
last  Fall. 

The  engineer  who  prepared  the  report  of  the  investigation 
of  the  Kansas  City  explosion  advanced  a  number  of  ideas  re- 
lative to  construction  that  at  the  time  appeared  to  be,  I  feel  free 
to  say,  somewhat  radical.  When  the  report  was  sent  to  the  Fed- 
eral Grain  Company  we  immediately  received  a  request  asking 
permission  of  the  Department  to  turn  this  report  over  to  the 
Burlington  Railroad  Company,  who  were  rebuilding  the  eleva- 
tor. Some  of  the  ideas  submitted  by  this  engineer  were  not  in- 
corporated in  our  report  as  we  did  not  feel  sufficiently  sure  of 
some  of  the  proposed  changes.  We  later  learned,  however,  that 
in  the  rebuilding  of  the  plant  the  construction  engineers  were 
carrying  out  some  of  the  ideas  that  we  delayed  action  on  at 
Washington.  At  that  time  we  told  Mr.  Reed,  one  of  the  in- 
vestigators, that  when  we  had  a  conference  of  this  nature  we 
would  give  him  an  opportunity  to  prepare  and  discuss  id 
prepared  by  him  or  by  other  engineers  through  him,  regarding 
changes  in  elevator  construction  suggested  by  recent  explosions. 
Mr.  Reed  will  now  discuss  this  subject. 

"CHANGES  IN  ELEVATOR  CONSTRUCTION  SUG- 
GESTED BY    RECENT    EXPLOSIONS." 

By  J.  O.  Reed. 

During  the  period  from  May  22  to  September  13,  1919,  four 
months,  there  were  five  disastrous  dust  explosions  in  modern 
and  so-called  fireproof  plants.  These  explosions  occurred  in 
two  feed  grinding  plants,  two  grain  elevators  and  one  starch 
factory.  Seventy  men  were  killed,  60  injured  and  the  property 
loss  was  estimated  at  $7,000,OOG  Due  to  the  fact  that  such  a 
large  number  of  explosions  occurred  in  such  a  short  period  oi 
time  in  these  plants  of  the  most  modern  type  of  construction!  it 

in-  quite  appropriate  that  the  subject,  "Changes  in  Elevator 
Construction  Suggested  1>\  Recent  Explosions,"  be  presented  at 
tin-  meeting 

\-  stated  before,  some  of  the  plants  in  which  these  explosions 
i  ccurred  were  constructed  entirerj  of  concrete  and  steel.     Heav) 

11 


walls  with  very  few  windows  were  used  in  the  building  structure. 
In  fact,  the  building  construction  of  all  these  plants  was  of  such 
a  nature  that  excessive  pressures  were  built  up  when  the  dust 
became  ignited.  Long  dust  collecting  and  conveying  systems 
were  used  in  some  of  these  plants,  a  fact  which  tended  to  enable 
rapid  flame  propagation.  Because  of  these  frequent  and  recent 
disasters  the  opinion  is  beginning  to  prevail  that  a  modern  grain- 
handling  plant,  constructed  of  fire-resistive  materials,  if  not  prop- 
erly maintained,  is  more  dangerous  from  a  dust  explosion  stand- 
point than  the  old  wooden  type  of  plant.  In  t  wooden  house  an 
explosion  occurs  and  blows  out  one  side  of  the  building.     Fire 


Extensive   damage    resulting    from   explosion   of   Btarcfa   dust 


follows  the  explosion,  hut  in  a  Large  number  of  instances  the 
sprinkler  system,  if  not  damaged  by  the  explosion,  extinguishes 
the  resulting  lire  In  a  concrete  house,  however,  the  explosion 
is  very  violent  because  of  the  high  pressures  that  are  built  up 
within  the  building,  due  to  the  solid  walls.  Concrete  plants  how 
ever,  in  my  opinion,  can  be  constructed  in  such  a  way  as  to 
reduce  the  explosion  hazard.  The  necessity  for  some  change 
ol  construction  is  all  the  more  emphasized  by  the  loss  of  life  and 
the  damage  to  property, 

In   the  construction   of   a    building   to   prevent    disastrous  dust 

12 


explosions,  provision  should  be  made  to  prevent  high  pressures 
from  being  built  up  within  the  plant  because  of  heavy  wall  con- 
struction. For  this  reason  the  suggestion  is  offered  that  the  plant 
be  constructed  of  very  thin  walls,  a  fact  which  could  be  made 
possible  by  the  use  of  some  wire  or  sheet  metal  frame  to  which 
is  attached  a  very  thin  coat  of  cement,  or,  in  other  words,  stucco 
wall  construction  could  be  used.  If  an  explosion  should  occur 
in  a  plant  built  with  walls  of  this  nature  very  little  resistance 
would  be  offered  to  the  increase  of  the  volume  of  gases  pro- 
duced by  the  ignition  of  the  dust.  In  a  building  designed  in  this 
manner  all  the  working  stresses  of  the  building,  loads,  etc.,  would 
be  placed  upon  the  concrete  columns  and  beams  used  in  the 
building  structure.  No  stresses  or  weights  would  be  placed  upon 
the  walls.  The  walls  would  only  serve  as  a  filler  between  the 
beams  and  the  concrete  columns- 

As  an  additional  means  of  preventing  high  pressures  from 
being  formed  within  the  plant  it  is  also  advised  that  large  win- 
dow areas  be  used  in  the  construction  of  the  plant,  or,  in  other 
words,  the  daylight  type  of  building  construction  be  used.  In 
fact,  it  is  suggested  that  at  least  one-third  of  the  entire  wall  area 
of  the  plant  be  covered  with  windows.  These  windows  should 
be  of  the  steel  sash  type,  should  be  self-supporting,  and  should 
extend  from  the  ceiling  to  the  floor.  Very  small  panes  with  the 
thinnest  possible  glass  which  would  not  break  by  vibration  should 
also  be  used.  Provision  should  be  made  for  the  ventilation  of  the 
plant  by  having  butterfly  windows  swing  open  horizontally  from 
the  floor  and  from  the  ceiling.  As  an  elevator  is  usually  several 
hundred  feet  high,  there  is  usually  a  strong  wind  prevailing 
upper  stories  of  the  plant.  With  these  windows  open  on  a  wind} 
day,  from  the  top  and  from  the  bottom,  the  best  possible  ventila- 
tion would  be  afforded  to  the  interior  of  the  plant,  especially 
in  the  "texas"  of  the  building.  There  is  a  strong  possibility  thai 
the  wind  at  times  would  be  so  strong  that  a  large  amount  of  the 
floating  dust  would  Ik-  blown  out  of  the  elevator  through  these 

window-.      In   speaking  to  a  man  who  had   worked  in  a  plant   in 

which  windows  of  somewhat  this  type  were  use,  1  was  informed 
that  on  certain  days,  when  there  was  a  high  gust  of  wind  bl< 
ing,  they  almost  cleaned  out  the  "texas"  simply  by  opening  the 

windows. 

In  order  to  prevent  the  accumulation  of  dust  in  a  plant  in 
such  a  manner  that  a  dust  explosion  could  not  become  disastrous, 
and  also  for  the  purpose  of  making  it  easier  to  keep  a  plant 
clean,  all  ledges  or  surfaces  in  the  plant  where  dust  m,i\ 

13 


cumulate  should  be  placed  at  an  angle  greater  than  the  angle  of 
repose  of  dust.  In  a  plant  of  this  nature  no  dust  accumulations 
can  lodge  overhead.  AH  steel  beams  and  girders  should  be 
covered  with  cement.  As  it  has  been  proven  that  concrete  is  a 
good  preservative  of  steel  construction  work,  its  use  will  serve 
as  a  means  to  prevent  the  rusting  of  the  metal  framework  of  the 
plant  as  well  as  to  prevent  the  dust  from  accumulating  overhead 
on  the  steel  beams. 

The  bin  floor  of  a  grain  elevator  she  uld  be  constructed  flush 
with  the  top  of  the  storage  tanks  for  the  purpose  of  eliminating 
the  explosion  hazard  produced  by  dust  accumulating  between 
the  top  of  the  bins  and  the  bin  floor.  Dust  that  accumulates  in 
such  a  place  becomes  very  old,  dry  and  inflammable.  When  an 
explosion  occurs  in  some  other  section  of  the  plant  this  dust  is 
thrown  into  suspension  and  acts  as  a  feeder  to  the  initial  explo- 
sion. As  the  space  is  entirely  open  above  all  the  bins  an  oppor- 
tunity is  given  for  the  flame  to  propagate  to  all  the  bins  and 
produce  a  very  disastrous  explosion.  If,  however,  the  bins  are 
constructed  flush  with  the  bin  floor,  each  bin  is  separate  and  an 
explosion  in  one  bin  is  not  very  likely  to  propagate  to  many  other 
bins- 

The  working  floor  should  be  very  open  with  the  entire  weight 
of  the  building  supported  by  heavy  concrete  and  steel  columns. 
(  >nly  a  small  percentage  of  the  sides  of  the  working  floor  should 
be  covered  with  walls,  and  in  place  of  these  walls  some  type  of 
rolling  steel  curtain  doors  should  be  used,  which  could  be  opened 
during  the  day  to  permit  the  greater  part  of  the  working  floor 
to  be  open.  Since  there  is  no  great  amount  of  machinery  on  the 
Working  floor,  and  since  there  are  only  a  few  workmen  outside 
of  the  unloaders  in  the  working  shed  who  ever  remain  on  the 
working  floor,  there  would  be  no  objection  to  that  portion  of 
the  plant  remaining  open.  Large  steel  sash  windows  should  be 
d  at  intervals  between  the  curtain  doors  to  provide  light 
when  the  curtain  doors  are  clos<  'I 

The  storage  bins  should  be  as  small  as  is  practical.  As  stated 
before,  all  bins  should  be  covered  and  should  have  perfectly 
smooth  sides  to  prevent  dust  from  accumulating,  a  fact  which 
was  emphasized  by  the  explosion  in  the  plant  at  Port  Colborne, 
'  Intario. 

The   basement    should    be   constructed   only    partially    under 

the  ground.     It",  for  instance,  an  8  foot  basement  is  to  be  used, 

only   I   feel  of  the  basement  should  be  below  the  -round  level 

I  he   1   feet  of  the  basement  above  the  ground  level  should  be 

14 


covered  with  very  thin  walls  and  a  large  window  area.  Provi- 
sion should  be  made  that  these  windows  could  be  opened  to  pro- 
vide ventilation  and  air  to  the  basement.  Then  if  an  explosion 
were  to  result  no  great  pressures  and  no  rapid  flame  propagation 
would  occur.  By  placing  the  basement  only  partially  under 
ground,  the  working  floor  of  the  plant  would  be  a  slight  distance 
above  the  ground  level,  a  fact  which  would  require  the  cars  that 
run  under  the  working  shed  to  be  run  up  a  slight  incline  plane  to 
the  working  shed.  This  would  have  its  distinct  advantage,  in 
some  cases,  for  by  the  use  of  an  incline  plane  to  the  plant  the 
cars  could  be  handled  more  readily  due  to  the  fact  that  the 
engine  would  push  the  cars  up  the  plane  to  the  working  shed  and 
the  cars  could  then  be  easily  handled  by  the  workmen  simply  by 
permitting  the  cars  to  run  by  gravity  to  the  unloading  pits.  If 
there  are  tunnels  that  run  under  the  storage  tanks,  provision 
should  be  made  that  portions  of  the  tunnel  be  open  or  confined 
only  by  means  of  very  thin  walls  or  windows.  A  vent  at  the 
end  of  a  tunnel  could  even  be  suggested. 

If  by  the  action  of  the  Boards  of  Trade  and  State  Ware- 
house Commissions  suction  is  not  permitted  to  be  used  on  ele- 
vator legs,  it  seems  quite  advisable  that  natural  vents  be  placed 
on  all  elevator  legs,  bins,  garners  and  scale  hoppers  in  the  plant. 
Scale  hoppers  and  garners,  especially  should  be  vented  to  the 
outside  for  the  reason  that  when  grain  is  run  into  a  scale  hopper 
or  garner  the  dust-laden  air  in  the  hopper  and  garner  is  forced 
out  into  the  building.  By  the  installation  of  a  vent  the  dust- 
laden  air,  instead  of  being  forced  out  into  the  building  proper, 
will  be  discharged  to  the  outside.  If  an  explosion  should  occur 
in  one  of  the  places  where  there  is  a  vent  provided  the  vent 
would  also  serve  to  a  considerable  extent  as  a  medium  to  relieve 
the  pressure  created  within  the  place  where  the  explosion  occurs 

In  the  installation  of  a  vent  for  elevator  heads,  it  would  - 
advisable  first  of  all  to  consider  the  construction  of  the  elevator 
5.  Tn  most  of  the  elevators  today  the  trunking  of  the  ele- 
vator legs  does  not  run  direct  from  the  boot  to  the  head,  hut  in- 
stead, in  that  portion  of  the  plant  where  the  storage  section  is 
placed,  there  IS  what  is  termed  an  "elevator  well"  through 
which  the  elevator  belts  run  instead  of  in  the  elevator  trunking. 

Tf  the  elevator  building  should  at   any  time  sag  <>r   vibrate  there 
i<  no  guarantee  in  an  installation  of  this  nature  that  the  elevator 
head  pulley   shall    remain   in   line   with   the   pulley   in   the  elc\ 
hoot.     At   the  same  time  there  is  n  great  amount  of  dust  that 

accumulates    in    this    "elevator    well"    which    IS    \cry    difficult    to 

15 


clean  out.  With  some  source  of  ignition,  as  for  instance  a 
spark  from  a  bucket  or  from  friction  due  to  an  elevator  choke 
or  legs  becoming  out  of  alignment,  usually  there  is  so  much 
dust  that  a  disastrous  explosion  results.  As  a  means  of  pre- 
venting the  possibility  of  the  elevator  head  pulley  becoming  out 
of  line  with  the  elevator  boot  pulley  due  to  the  installation  as  just 
described,  it  seems  quite  advisable  that  the  entire  elevator  leg  or 
trunking  be  built  solid  and  in  one  piece  from  the  boot  up  to  the 
elevator  head.  The  elevator  would  then  be  self-supporting,  would 
rest  upon  the  floor  in  the  basement,  and  would  not  be  put  out 
of  alignment  by  the  sag  of  the  building.  Heavy  steel  plate  con- 
struction would  be  used  for  the  elevator  trunking  so  that  if  an 
explosion  were  to  occur  it  would  be  confined  until  it  reached  the 
vent  at  the  head.  It  seems  quite  natural  that  the  elevator  heads, 
due  to  the  fact  that  they  are  so  close  to  the  roof  of  the  building, 
should  run  out  through  the  roof  and  there  be  capped  by  means 
of  a  ventilator  of  a  special  design  which  would  serve  to  ventilate 
the  lofters  and  provide  an  escape  for  the  gas  in  the  event  of  an 
ignition  of  dust.  Natural  vents  on  bins  serve  several  purposes. 
They  remove  one  of  the  greatest  objections  to  the  use  of  the 
closed  bin,  for  the  reason  that  they  provide  ventilation  to  the 
grain  contained  in  the  bin  while  at  the  same  time  they  provide 
a  relief  for  the  air  pressure  developed  as  the  grain  is  being  run 
cither  into  or  out  of  the  bin.  Ventilators  of  some  special  type 
should  be  placed  over  these  vents  and  should  be  so  designed  that 
sparks  from  locomotives  would  be  unable  to  get  in.  Vents  would 
probably  be  of  some  use  in  the  tunnels  underneath  the  storage 
bins  where  there  is  always  poor  ventilation  and  heavy  dust  clouds. 
It  seems  to  be  the  tendency  in  modern  elevator  construction 
to  install  extensive  dust  collecting  systems  which  extend  to  all 
sections  of  the  plant.  During  a  very  recent  explosion  the  fact 
was  brought  out  very  conclusively  that  dust-collecting  systems 
of  an  extensive  character  arc  very  dangerous  to  have  in  a  plant 
because  by  a  lengthy  installation  an  excellent  chance  is  afforded 
for  the  flame  to  propagate  through  the  trunking  of  the  dust  - 
collecting  system  to  all  sections  of  the  plant.  It  seems  quite 
advisable,  due  to  tins  fact,  that  instead  of  one  large  system  being 

Used    for  the   collection   of  all   the  dust   in  the  plant,  a  series   oi 

small  systems  should  he  used.     For  instance,  a  separate  system 

should  he  installed   for  the  SUCtiotl  floor  sweep  in  the  "texas"  and 

a  separate  system  for  the  working  floor  and  basement.     It  also 

..in-  advisable  that  the  fan-  on  all  cleaning  machines  should 

<\hanst   directly  into  a  cyclone  dust  collector  installed  outsid< 

16 


of  the  plant  instead  of  into  a  main  trunking  which  leads  to  a  sys- 
tem of  dust  collectors.  If  suction  is  permitted  to  be  used  it  seems 
quite  advisable  that  a  separate  system  be  installed  for  the  aspira- 
tion of  the  garners,  a  separate  system  for  the  scale  hoppers,  and 
a  separate  system  for  the  elevator  heads,  etc.  If  it  is  necessary 
that  a  main  suction  trunk  of  any  length  be  used  it  seems  that 
instead  of  running  this  trunking  through  the  center  of  the  plant 
it  should  be  run  on  the  outside  of  the  plant,  for  if  then  an  explo- 
sion propagates  through  the  dust  collecting  system  it  will  be  car 
ried  outside  and  probably  do  little  damage.  In  this  trunking 
outside  of  the  plant  some  sort  of  a  relief  valve  could  be  designed 
and  installed  which  would  relieve  the  pressure  in  the  dust-collect- 
ing system  and  vent  the  explosion,  thereby  further  reducing 
danger  of  damage. 

All  the  trunking  of  the  dust  collecting  system  should  be  con- 
structed in  sections  so  that  it  is  possible  to  take  down  the  trunk- 
ing and  clean  it  out.  This  trunking  should  be  of  such  a  size  that 
high  air  velocities  shall  prevail  in  the  system  for  the  reason  that 
no  dust  is  then  able  to  fall  to  the  bottom  of  the  steel  tube.  All 
elbows  of  the  trunking  system  should  have  a  radius  of  at  least 
twice  the  diameter  of  the  pipe.  All  trunking  should  be  properly 
grounded  for  static  electricity. 

Very  recently  there  has  been  two  explosions  which  originated 
in  the  suction  fans  used  in  connection  with  dust-collecting  - 
terns.  This  fact  would  seem  to  indicate  that  either  the  fans  w 
not  constructed  properly  to  reduce  to  a  minimum  the  possibility 
of  the  formation  of  sparks  within  the  fan  casing,  or  the  fans 
were  receiving  poor  care  during  their  operation.  To  reduce  to 
a  minimum  the  possibility  of  the  fan  blades  striking  the  sides  of 
the  outer  sheet-iron  fan  casing,  and  to  eliminate  other  fan 
troubles,  the  following  recommendations  and  suggestions  regard- 
ing the  construction  of  fans  arc  made  for  your  consideration  at 
this  meeting : 

1.  The  fan  blade-  should  be  enclosed  and  fixed  securel)  on 
the  sides  to  a  -beet  iron  casing.  The  fan  hub  to  which  the  blades 
are  attached  should  extend  about  one  half  inch  beyond  this  fan 
blade  casing.  There  should  be  a  clearance  of  at  least  one  and  one 
half  inches  between  the  fan  Made  casing  and  the  outer  fan  cas 
ing,  By  an  installation  of  this  nature  it  seems  quite  impossible 
for  a  fan  blade  to  become  loose  and  strike  the  side  of  the  fan 
easing  and  produce  sparks. 

1.  The  hub  to  which  the  fan  blades  are  attached  should  be 
fixed  to  the  revolving  overhanging  shaft  by  means  of  two  tapered 

17 


keys,  one  key  at  each  end  of  the  hub,  the  angle  between  the  keys 
to  be  120  degrees.  These  keys  should  be  held  in  place  in  the  fan 
hub  by  means  of  set-screws  which  should  be  screwed  into  a 
small  hole  or  seat  in  the  key  produced  by  the  point  of  a  drill  bit 
after  the  key  is  driven  into  the  hub. 

3.  In  regard  to  the  proper  maintenance  of  the  fan  it  appears 
quite  essential  that  frequent  inspections  should  be  made  of  the 
fan  to  determine  the  clearance  between  the  fan  blades  and  the 
outer  fan  casing.  For  this  purpose  a  door  or  some  other  open- 
ing should  be  provided  in  the  side  of  the  outer  fan  casing  to 
facilitate  inspection. 

4-  It  seems  quite  necessary  that  some  provision  be  made  in 
the  construction  of  the  fan  to  provide  for  the  end  thrust  of  the 
fan  and  for  the  adjustment  or  clearance  between  the  fan  blades 
and  the  casing  by  means  of  collars  being  placed  on  the  fan  shaft 
next  to  the  journals. 

In  making  these  suggestions  regarding  the  construction  of 
grain  elevators  it  will  be  noted  I  have  considered  only  elevators 
constructed  entirely  of  fire-resistive  materials,  such  as  concrete, 
tile  and  steel.  You  gentlemen,  due  to  the  fact  that  recent  ex- 
plosions have  occurred  only  in  plants  constructed  of  fire-resistive 
materials,  may  put  forth  the  argument  fhat  elevators  should 
be  constructed  of  wood,  since  explosions  have  not  occurred  of 
late  in  plants  of  this  type  of  construction.  The  following  rea- 
sons are  given  in  advocating  the  construction  of  concrete  ele- 
vators : 

1.  The  depreciation  on  an  elevator  built  entirely  of  concrete 
is  small,  while  the  5  per  cent,  a  year  depreciation  on  wooden 
elevators  is  a  conservative  figure.  The  depreciation  and  up- 
keep of  the  machinery  is  much  less  in  a  concrete  building,  owing 
to  the  solidity  of  the  structural  supports  and  the  absence  of 
vibration. 

2.  The  safety  afforded  the  elevator  owner  is  a  matter  which 
must  be  considered.  The  day  is  past  when  the  elevator  can  be 
replaced  within  60  days.    It  is  exceptional  at  the  present  time  to 

ure  the  delivery  of  lumber  required  for  the  wooden  elevator 

construction    within   that    time.      In   pasl    years   almost    immediate 

shipments  could  be  depended  upon  from  the  lumber  mills  of 
northern  Minnesota  and  Wisconsin.  Now  ()()  per  cent,  of  the 
lumber  must  come  From  the  Pacific  Coast. 

3.  It  has  been  proven  that  reinforced  concrete  is  the  most 
flexible  of  all  material  in  the  construction  of  grain  elevators  and 

18 


storage  tanks.  It  is  claimed  that  99  per  cent  of  the  larger  grain 
elevators  and  storage  houses  at  the  terminals,  and  possibly  90 
per  cent,  of  all  the  fireproof  country  elevators  are  now  being 
built  of  reinforced  concrete.  Where  grain,  earth  and  water  pres- 
sures are  to  be  resisted,  reinforced  concrete  is  the  logical  ma- 
terial. 

4.  In  a  recent  fire  in  the  concrete  elevator  of  a  cereal  com- 
pany at  Minneapolis,  the  fire  resisting  qualities  of  concrete  were 
demonstrated.  On  the  first  floor  of  this  elevator  there  were 
several  attrition  mills  with  wooden  feed  legs,  sacking  spouts, 
reels  and  conveyors.  The  fire  burned  out  this  installation  but 
the  only  damage  done  to  the  building  structure  was  a  slight 
crumbling  of  the  concrete  over  an  area  of  a  few  square  feet  and 
to  a  depth  of  less  than  one-half  inch,  resulting  in  no  serious  in- 
jury to  the  strength  of  the  bin  bottom.  If,  however,  the  bin 
bottom  slab  had  been  supported  on  exposed  steel  beams,  which 
I  have  stated  before  in  this  paper  should  be  covered  with  con- 
crete for  the  purpose  of  preventing  dust  accumulations  from 
forming,  the  heat  developed  would  have  been  sufficient  to  cause 
llit-  steel  to  sag  and  possibly  collapse  under  the  load. 

In  my  effort  to  present  the  subject  of  "Changes  in  Elevatoi 
Construction  Suggested  by  Recent  Explosions,"  I  have  only  con- 
sidered some  of  the  important  changes  which  I  thought  necessary. 
I  have  only  touched  the  subject  in  a  general  way  and  have  by  no 
means  tried  to  draw  up  a  code  or  a  detailed  plan  on  elevator 
building  construction.  I  desire  a  full  discussion  on  some  of  the 
suggestions  which  I  have  made  and  for  this  reason  I  wish  to 
give  you  a  summary  of  some  of  the  changes  I  have  advocated 
As  you  have  noted,  I  have  recommended  that  grain  elevators 
be  constructed  of  fire-resistive  materials  with  thin  walls  and 
large  window  areas  providing  good  ventilation.  Half -basements, 
or  no  basements  at  all;  comparatively  open  working  floors,  and 
endowed  bins  have  been  suggested.  The  question  of  vents  on 
garners,  weighing  hoppers,  bins,  and  elevator  brad-,  together 
with  a  change  in  the  installation  of  the  elevator  trunking  has 
been  considered.  1  have  advised  thai  the-  elevator  heads  be  run 
<ut  through  the  roof  of  the  building  and  vented,  and  also  have 
dwelled  upon  the  subject  of  dust  collecting  systems  only  in  a 
general  \\a\  by  recommending  that  shorter  and  separate  systems 
be  installed.  I,  however,  have  gone  into  detail  on  the  proper 
construction  and  installation  of  exhaust  fans.  Lastly,  I  have 
endeavored  to  show  you  the  economic  necessit)  of  reinforced 
concrete  elevator  construction     It  is  these  subjects  which  1 

19 


sire  that  you  discuss  and  which  I  think  demand  some  considera- 
tion in  the  construction  of  grain  elevators  for  the  prevention  of 
disastrous  dust  explosions. 

Mr.  PRICE — Mr.  Reed  has  covered  this  matter  very  thor- 
oughly. Do  you  concur  in  everything  that  has  been  said  about 
changes  in  construction  to  prevent  disastrous  explosions  from 
occurring? 

Mr.  BODNAR — In  the  Northwest  I  came  across  two  con- 
crete elevators,  each  with  a  capacity  of  about  90,000  bushels, 
that  had  a  peculiar  construction  which  might  help  prevent  dis- 
astrous dust  explosions.  Each  of  the  elevators  had  five  or  six 
bins,  the  tops  of  which  were  open  to  the  open  air  around  the 
entire  upper  periphery.  The  openings  were  anywhere  from  ll/2 
to  2  feet  high.  When  the  elevator  operates  so  that  grain  is 
falling  into  the  bins  the  wind  or  any  breeze  will  clear  out  and 
carry  away  most  of  the  dust  in  the  air.  If  there  was  an  explo- 
sion on  the  main  floor  there  would  probably  be  enough  relief  of 
pressure  through  the  opening  above  mentioned  that  no  serious 
results  would  occur.  One  of  these  elevators  is  at  Walla  WTalla. 
Wash.,  and  the  other  somewhere  in  Idaho. 

Dr.  BROWN— Are  the  bins  all  connected? 

Mr.  BODNAR — Yes.  There  was  no  floor  on  top  of  the  bins. 
All  of  the  bins  were  open.  The  opening  I  mentioned  might  just 
as  well  have  been  a  window  area  with  all  of  the  windows 
knocked  out. 

Mr.  REED — In  the  elevator  I  have  considered  the  windows 
can  be  closed  when  it  rains. 

Mr.  BODNAR — The  operators  of  these  elevators  say  they 
were  never  bothered  by  weather  conditions. 

J  )r.  BROWN — Most  of  the  wheat  in  the  Northwest  can  stand 
a  little  extra  moisture. 

Mr.  PRICE — They  leave  a  foot  and  a  half  or  two  feet  be- 
tween top  of  bins  and  floors? 

Mr.  REED  I  advised  that  each  bin  he  enclosed.  Now  in  an 
installation  of  that  nature,  as  Mr.  Bodnar  states,  there  is  no  dust 
that  can  accumulate  between  the  bins  and  the  bin  floor. 

Mr  BODNAK  Then-  is  no  bin  floor  in  this  case,  that  is, 
the  bins  arc  ..pen  entirely. 

20 


Mr.  PRICE — There  are  a  number  of  questions  I  would  like  to 
bring  up.  In  regard  to  the  matter  of  thin  walls,  about  how  thick, 
approximately,  should  these  walls  be? 

Mr.  REED — The  walls  at  Kansas  City  on  the  working  floor 
were  about  six  inches  thick.  In  the  construction  of  the  shops 
used  in  the  army  cantonments  and  the  like,  which  were  con- 
structed of  concrete,  they  just  placed  in  between  the  steel  or 
concrete  colums  that  were  used  a  wire  screen  or  something  of 
that  nature  upon  which  they  squirted  a  spray  of  cement,  I  think 
not  over  one-half  inch  or  an  inch  thick.  When  I  speak  of  a  thin 
wall  I  mean  a  wall  not  over  2  inches  thick. 

Mr.  BRADY — Is  there  any  objection  to  a  brick  wall? 

Mr.  REED— That  would  be  a  little  too  thick. 

Mr.  PRICE — In  addition  to  this  matter  of  construction,  Mr 
Reed  also  suggested  that  the  working  floor  be  almost  entirely 
open,  a  very  small  percentage  covered.  His  theory  is  to  have 
the  working  floor  entirely  open  with  a  small  part  of  it  covered, 
and  instead  of  a  basement  have  an  inclined  plane  to  handle  the 
cars.     I  would  like  to  present  that  matter  for  discussion. 

Mr.  BRADY — I  think  there  ought  to  be  some  work  done 
relative  to  fans  in  elevators.  The  explosion  that  recently  took 
place  at  Manitowoc  shows  that  a  steel  fan  is  something  to  be 
reckoned  with  in  eliminating  explosions.  Here  was  a  case  where 
a  wire  got  into  a  steel  fan,  made  a  spark  and  caused  the  explo- 
sion, a  thing  that  is  apt  to  occur  in  elevators  or  mills.     Fans,  it 

ms  to  me,  could  be  encased  in  some  way  so  that  you  would 
have  a  plate  on  the  inside  of  those  fans,  and  the  blades  made 
of  something  other  than  steel,  maybe  bronze,  aluminum  or  some- 
thing of  the  sort  that  wouldn't  strike  a  -park  when  it  would  hit 
along  the  side  of  tlu-  fan  casing.  A  while  ago  an  explosion  oc- 
curred in  Denver,  supposed  to  have  been  caused  by  the  fan 
running  loose  and  going  up  against  the  steel  casing.     It  tl 

made  a    Spark   which   ignited   the  dust    in   the   dn<t-e<>lkvtiiiL,r 

tern.     Now  this  question  could  In-  presented  to  some  of  the  people 

that  make  fans  and  have  them  make  such  provision. 

Mr.    PRICE — At   what   points  in   the  elevator  would   the 

In-  located  'J 

Mr.    REED      At   any   point    where    SUCtion    i-   applied    and   an 

aspirating  system  used  there  should  be  a  fan. 

21 


Mr.  PRICE — The  objection  has  been  raised  that  some  State 
regulations  prohibit  suction  of  any  kind  between  the  receiving 
point  and  the  weighing  of  the  grain. 

Mr.  BRADY — You  can  use  indirect  suction  on  the  buckets  or 
elevator  leg  at  any  time. 

Mr.  PRICE — This  is  all  beyond  the  weighing  point,  I  take  it. 

Mr.  BRADY — The  point  I  want  to  raise  is  to  change  the  con- 
struction of  fans. 

Mr.  REED — Why  not  constru  :t  a  fan  that  a  piece  of  wire 
can't  get  into  very  easily;  one  that  can't  work  to  the  side  and 
produce  a  spark — one  that  will  not  permit  the  fan  blades  to 
work  to  the  sides  ?  Aluminum  is  said  to  deteriorate  in  air  where 
there  is  a  great  quantity  of  air  being  handled.  This  fact  almost 
justifies  that  it  be  not  considered. 

Mr.  BRADY — Other  metals  could  be  used,  probably. 

Mr.  REED — Bronze  would  cost  too  much. 

Mr.  PRICE — The  Manitowoc  explosion  was  in  an  aluminum 
manufacturing  plant — an  explosion  of  aluminum  dust  in  which 
the  investigators  assigned  the  cause  to  a  metallic  spark  caused 
by  a  wire  getting  into  the  fan.  The  cause  of  the  Denver  ex- 
plosion is  debatable.  Late  developments  bring  out  more  doubt 
as  to  whether  the  explosion  was  caused  by  the  fan  slipping  to 
the  side.  It  would  seem  just  as  probable  that  it  may  have 
started  in  the  rolls  by  sparks  from  foreign  materials. 

Mr.  BRADY — On  the  subject  of  the  fan,  I  am  not  quite  clear 
on  the  inner  casing  that  is  referred  to. 

Mr.  REED — The  fan  hub  is  keyed  to  the  overhanging  shaft 
by  two  keys,  one  at  each  end  of  the  hub,  the  angle  between  the 
keys  to  be  120  degrees.  The  fan  blades  are  enclosed  and  are  also 
placed  at  ail  angle,  a  fact  which  I  think  is  good  construction. 

Mr.  PRICE     What  is  the  objection  to  it?    Is  it  a  good  idea? 

Mr.  BROWN— I  understand  that  the  blades  of  the  tan  are  en- 
closed by  a  plate  at  each  side.  I  low  are  you  going  to  get  the 
dust  out  of  l lie  Ian  alter  it  goes  in? 

Mi.  REED  It  comes  out  at  the  end  that  is  not  enclosed. 
l-an-  are  being  constructed  that  way  today. 

Mr.  BROWN-  -\\  hen   does  the  dusi  go  in? 

Mr.    REE1 )      Into  the  c\c  oi    the   Ian. 

22 


Dr.  DUVEL — The  ordinary  fan  has  two  bearings,  doesn't  it? 

Mr.  REED — Yes.  They  are  at  one  side  of  the  fan  casing. 
I  am  not  speaking  about  an  extra  large  fan.  Almost  all  small 
fans  used  today  have  the  overhanging  shaft  and  all  the  bearings 
on  one  side  of  the  fan  casing. 

Mr.  ROETHE— Is  that  a  multi-vane  fan? 

Mr.  REED— No. 

Mr.  PRICE — We,  generally,  agree  with  the  idea  Mr.  Reed 
has  brought  out,  if  this  fan  is  going  to  solve  the  trouble.  We 
have  gotten  just  a  little  away,  however,  from  some  other  features 
relating  directly  to  construction.  Mr.  Reed  said  that  he  knew 
of  an  elevator  in  Baltimore  where  some  of  the  ideas  suggested 
were  being  carried  out.     What  elevator  is  this,  Mr.  Reed? 

Mr.  REED— The  Mount  Clare  Elevator  operated  by  the  B.  & 
O.     Its  capacity  is  about  500,000  bushels. 

Dr.  BROWN — I  might  state  my  views  in  connection  with 
some  of  the  points  that  have  been  brought  out.  although  slightly 
divergent  from  the  last  two  or  three  points  of  which  Mr.  Price 
has  spoken.  The  one  with  the  basement  largely  above  ground- 
level  appeals  to  me  as  something  well  worth  while.  The  Port 
Colborne  elevator — Government  elevator  at  Port  Colborne — 
was  so  constructed.  In  fact,  there  was  only  about  two  or  three 
feet  below  the  surface  and  about  ten  or  twelve  feet  above  the 
surface.  There  was  a  window  surface  of  the  wall  of  easily, 
I  should  say,  two-thirds  of  the  portion  of  the  wall  above  ground, 
but  the  interesting  fact,  as  1  will  try  to  bring  out  in  the  review 
of  that  explosion  tomorrow,  was  that  the  windows  were  drawn 
in  and  not  blown  out.  The  explosion  was  not  in  the  basement,  but 
should  it  have  been  in  the  basement  and  propagated  through  the 
basement,  there  certainly  was  enough  window  space  and  weak 
construction  to  have  vented  it  and  the  remaining  portion  of  the 
construction  was  probably  sufficiently  strong  to  have  held  the 
pressure  that  might  have  been  built  up  back  of  this  so-called 
light  construction.  If  we  are  going  to  advocate  light  construe 
nun  for  side  walls  our  super-structure  would  have  to  be 
heavy  structure  to  withstand  the  force.  If  we  have-  a  proper 
mixture  of  dust  and  air  to  give  us  the  most  inflammable  dust 
and  air  mixture,  the  rate  of  propagation  and  the  pressure 
veloped  in  the  explosion  is  going  to  be  so  instantaneous  that  we 
are  gi  in  a  sudden  destruction  of  everything  unles 


large  area  of  the  structure  will  give  way  easily  and  the  smaller 
portion  will  be  of  sufficient  strength  to  withstand,  for  a  short 
time  at  least,  that  excess  pressure. 

In  regard  to  the  open  structure  and  especially  in  the  "texas" 
that  question  was  considered  very  seriously  in  connection  with 
the  Port  Colborne  disaster  and  was  brought  up  at  the  hearing 
held  in  Port  Colborne  sometime  after  that.  It  seems  to  me, 
although  we  probably  do  get  a  certain  amount  of  ventilation  and 
a  certain  amount  of  the  dust  carried  out,  that  if  we  have  enough 
dust  present  in  suspension  in  the  elevator  so  that  seemingly  a 
large  enough  quantity  must  be  carried  out  to  reduce  the  hazard, 
we  certainly  are  going  to  get  a  sufficient  quantity  accumulated 
to  make  a  very  dangerous  condition.  Unless  the  walls  are  light 
and  largely  open  we  are  going  to  have  enough  pressure  developed 
in  case  of  an  explosion  to  be  very  dangerous.  In  the  elevator 
at  Weehawken  the  walls  were  of  very  light  construction,  might 
say,  above  the  bin  floor.  To  the  roof  of  the  bin  floor  the  walls 
were  of  brick  and  about  8  to  10  inches  thick.  The  "texas"  walls 
were  of  4-inch  hollow  tile.  The  side  walls  of  the  bin  floor  with- 
stood all  pressure  developed  and  were  not  pushed  out  to  any 
extent,  but  the  walls  of  the  "texas"  were  largely  blown  down. 
i  was  in  that  elevator  only  a  short  time  after  the  explosion  hap- 
pened. They  had  not  cleaned  up  at  all  and  there  was  only  a 
very  small  quantity  of  dust  accumulated  anywhere.  It  was  in- 
teresting to  note  the  path  of  the  explosion  through  the  "texas." 
On  some  of  the  girders  the  dust  on  three  sides  had  been  charred 
while  the  dust  on  the  other  side  was  not  charred.  There  was 
some  dust  on  this  side  but  not  much.  There  was  a  normal  quan- 
tity of  dust  on  the  sides  of  the  elevator  and  the  floors  were  quite 
clean.  This  illustrated  to  me  the  ease  with  which  an  explosion 
will  propagate  through  a  comparatively  small  quantity  of  dust, 
seemingly,  which  may  have  accumulated  on  the  side  walls  or  on 
the  beams,  etc-  There  was  no  evidence  of  dust  on  the  beams  in 
this  Weehawken  elevator  and  the  side  walls  were  very  clean. 
I  have  never  been  in  but  one  elevator  which  was  cleaner. 

Mr.  B<  >DNAR — In  two  elevators  of  about  the  type  I  have  re- 
ferred to,  1  have  found  Mr.  Reed's  idea  carried  <>ut  in  so  far  as 
the  well  or  manlifl  shaft  of  the  elevator  is  concerned.  This  well 
was  constructed  of  wire  netting  covered  by  concrete  not  over 
one-half  inch  thick.     These  two  elevators  arc  in   Idaho. 

Mr.  McCOLLAM  En  regard  to  Mr.  Reed's  point'  about 
eliminating  elaborate  dust  collecting  systems,  in  an  Ogden  ele- 

24 


vator  of  one-half  million  bushels  capacity,  the  only  dust-collect- 
ing system  is  their  battery  of  cyclone  dust-collectors  on  the 
cleaning  machinery.  This  is  located  on  the  outside  of  the  ele- 
vator. No  suction  is  applied  anywhere  in  the  elevator.  They 
have  a  very  tight  job  of  milhvrighting  throughout  the  elevator. 
Every  joint  in  the  steel  elevator  legs  is  packed  very  tightly  with 
felt,  and  all  other  joints  in  the  scale  hoppers  and  garners  are 
likewise  packed  very  tightly. 

Mr.  BATES — I  would  like  to  ask  if  this  thin  wall  suggested 
of  stucco  on  metal  lathing  isn't  supported  between  the  spans  as 
is  ordinary  siding? 

Mr.  REED — If  I  remember  correctly  they  put  this  wire  up 
with  very  little  support  at  all-  Immediately  back  of  the  wire 
they  put  up  heavy  boarding  and  shot  the  concrete  right  up  againsi 
it  with  a  cement  gun. 

Mr.  BATES — Unless  these  spans  are  short,  such  a  wall  would 
not  sustain  a  very  great  pressure  from  the  outside,  as  in  the  case 
of  a  high  wind,  and  in  that  kind  of  construction  at  any  place 
where  there  was  weight  or  constantly  changing  pressure  you 
would  expect  it  to  crack  and  give  trouble. 

Mr.  .REED — I  think  there  was  some  siding. 

Mr.  BATES — Would  it  not  be  well  to  recommend  light  con- 
struction between  the  framework  of  the  supports,  not  attempting 
to  say  what  that  light  construction  should  be.  in  preference  to 
giving  our  ideas  in  regard  to  any  particular  structural  design? 
If  we  attempt  to  specify  definitely  shapes  and  thickness  we  are 
bound  to  get  into  trouble. 

In  Mr.  Reed's  suggestions  he  brought  out  some  very  inter- 
esting  points  in  fan  design.  I  believe  whatever  i-  given  t<»  the 
industries  in  the  way  of  specifications  should  be  very  general.  In 
fact,  in  that  kind  of  fan  there  Is  no  way  you  can  hold  the  pro- 
pellers From  slipping  to  the  outside,  because  if  the  Fan  becomes 
loose  "ii  the  shaft  the  shaft  does  not  go  through  the  fan  hub. 
Tin-  idea  of  making  the  blades  narrow  at  the  tip  is  to  keep  the 
velocity  of  the  air  the  same  at   all  points,   which   is  desirable, 

cially  in  high  speed  fan-. 

Mr.  WATERS  In  regard  to  the  stucco  construction  Mr. 
Reed  spoke  about,  it  may  be  all  right  on  upper  stories,  but  in  an 
elevator  it  i>  jusl  a-  necessary  t<»  try  to  eliminate  fire  from  the 

OUtside.      If    there    i-   a    lire    nearl.\    you    wet    down    the   elevator 


to  keep  the  fire  from  coming  in  contact  with  the  elevator.  In 
that  case  those  stucco  walls  will  under  no  condition  stand  any 
pressure  of  water.  They  would  therefore  not  be  very  appropriate 
on  the  first  floor. 

Mr.  REED — You  are  talking  about  fireproof  construction. 
What  we  are  considering  is  explosion  proof,  not  fireproof  con- 
struction. 

Mr.  WATERS — Stucco  of  that  sort  would  not  be  fireproof. 

Mr.  HELMKAMP— I  doubt  if  it  would  stand  some  of  the 
winds  in  Kansas. 

Mr.  REED — A  wall  could  be  designed  to  withstand  the  wind 
pressures.  Wind  pressures  are  not  as  great  as  explosion  pres- 
sures. 

Mr.  BRADY — You  could  make  it  of  solid  concrete,  could 
you  not? 

Mr.  PRICE — I  think  a  more  practical  construction  would 
probably  be  a  medium  between  the  very  thick  construction  of 
the  present  and  what  we  are  considering  here. 

Mr.  HELMKAMP — In  connection  with  this  thin  construc- 
tion on  the  working  floor,  the  Murray  elevator  at  Kansas  City  is 
being  constructed  with  that  in  view-  They  also  have  the  tun- 
nels equipped  with  five  vents,  one  at  each  end  and  three  be- 
tween the  bins. 

Mr.  FRITZ — I  have  taken  quite  an  interest  in  your  discus- 
sion of  the  explosion  at  the  Murray  Elevator.  Two  years  ago 
this  month  J  was  working  at  the  elevator,  conducting  investiga- 
tions relative  to  the  invisible  loss  occurring  in  dried  corn.  Part 
of  our  work  was  to  detect,  if  possible,  the  amount  of  loss  that 
occurred  in  handling  corn  in  the  house,  that  is,  loss  that  could 
be  accounted  for  as  dust.  As  a  part  of  our  work,  we  decided  to 
try  to  determine  the  amount  of  dust  that  collected  per  square 
yard  on  each  floor  for  the  duration  of  twenty-four  hours.  It 
was  deemed  advisable  to  leave  the  customary  number  of  doors 
and  windows  open  on  each  floor.  A  square  yard  of  paper  was 
placed  at  different  places  on  each  floor  and  allowed  to  remain 
there  for  twenty-four  hours.  At  the  end  of  the  period  the  col- 
lected  dusl  was  weighed  and  recorded.  It  was  found  that  there 
was  a  more  or  less  regular  increase  from  the  scale  floor  to  the 

nixl  or  working  floor.    The  point  I  wish  to  emphasize  is  that 

tins    substantiates    the    reeommendations    of    the    gentleman    who 

26 


just  talked  to  you  concerning  the  advisability  of  having  numerous 
windows  and  doors  in  the  future  elevator  construction.  The  scale 
and  garner  floor  of  the  Murray  Elevator  had  many  windows  as 
did  some  of  the  intermediate  floors.  When  these  were  open 
most  of  the  dust  was  carried  out  by  the  air  currents  and  only 
slight  effort  was  necessary  to  brush  the  sills  and  girders.  On 
the  working  floor  the  situation  was  entirely  different.  There 
being  fewer  openings,  the  dust  could  not  escape  as  freely  be- 
cause of  the  lack  of  openings  to  allow  air  currents  to  pass  through 
and  consequently  most  of  it  settled  on  the  beams,  floors,  etc. 

Mr.  PRICE — The  explosion  in  the  Murray  plant  started  down 
in  the  basement  where  the  large  quantity  of  dust  was  present. 

Dr.  BROWN — I  would  like  to  hear  some  discussion  on  the 
question  Mr.  Reed  brought  out,  of  extending  elevator  casings 
out  through  the  roof.  My  reason  for  interest  in  that  is  that  I 
made  that  as  a  possible  recommendation  in  the  case  of  the  re- 
building of  the  Port  Colborne  elevator. 

Mr.  BRADY — A  construction  of  that  nature  is  now  being 
used  in  some  of  the  oat  plants,  as  I  understand  it.  A  cereal 
company  in  the  Middle  West  are  capping  the  legs  in  their  plant. 
They  have  had  some  explosions  in  these  legs  since  they  capped 
them.  The  cap  would  blow  off  and  not  do  any  damage  to  the 
plant. 

Mr.  H1BBARD — The  Milwaukee  explosion  took  place  on  the 

main  floor  and  the  elevator  was  constructed  of  steel  plates  bill  the 
explosion  was  so  strong  that  it  blew  the  plates  out  and  tore  the 
bolts  Otll  and  they  had  another  explosion  at  the  top. 

Dr.  BR(  >\V.\     That  would  be  a  question  of  pressure  and  ve- 
locity developed.     With  the  most  inflammable  mixture  of  dusl 
and  air  probably  the  pressure  exerted  upward  would  overcome  the 
air  pressure  and  the  inertia  in  the  dead  air  would  be  so  great 
thai  the  side  walls  would  blow  out  and  not  overcome  the  hazard. 

"LA  I  EST   DE\  ED  >PMENTS    VND  l>K\  [<  ES   F<  »K    PRE 
VENTU  »\  (  >!•  i  IK  >KES  IX   ELEVATt  >R   LEG 

By  Mr   P.  K.  Brady. 

i  hoke  ups  in  elevator  legs  occur  frequently.    The  four  com- 
mon causes   for  such  occurrences  are:    <li   Overloading; 
Bins  becoming  full;  (3)   Belt  plugged  l»>   foreign  material; 
I  tower  going  off. 

27 


The  over-loading  feature  is  generally  caused  by  a  mechanical 
defect  in  that  the  belt  and  cups  used  to  carry  the  load  away  from 
the  boot  are  somtimes  too  small  to  take  care  of  the  incoming 
grain.  Conditions  of  this  kind  do  not  often  take  place,  but  in 
some  instances  these  facts  have  been  brought  out.  One  instance 
of  this  developed  during  an  investigation  of  a  dust  explosion 
which  occurred  in  a  large  starch  factory  in  this  country.  It  de- 
veloped that  this  company  was  using  a  large  conveyor  which 
emptied  into  an  elevator  boot  and  elevated  through  a  leg.  When 
this  conveyor  was  loaded  to  full  capacity  the  boot  or  leg  was 
not  of  ample  size  to  take  the  producA  away.  Consequently  a 
man  had  to  be  employed  to  gauge  the  flow  of  the  material  in  the 
conveyor  and  it  was  his  business  to  see  that  this  conveyor  was 
never  loaded  to  a  degree  whereby  it  would  choke  the  leg.  Of 
course,  such  conditions  are  most  inefficient  as  well  as  dangerous. 
At  times  it  was  known  that  this  man  had  permitted  the  con- 
veyor to  be  over-loaded  and  thus  a  choke  occurred  in  the  eleva- 
tor leg.  This  kind  of  an  occurrence  could  be  remedied  by  putting 
in  the  proper  sized  leg  and  cups  to  elevate  the  material  which 
might  come  from  such  a  conveyor  when  the  conveyor  was  run  at 
full  capacity.  Defects  of  this  nature  can  be  remedied  by  proper 
mechanical  installations.  Such  occurrences  do  not  take  place 
frequently  in  the  average  mill  or  elevator,  but  mention  is  made 
of  this  fact  to  show  one  of  the  causes  of  choke-ups. 

At  times  a  choke-up  occurs  when  the  bins  become  full,  the 
spout  leading  to  the  bin  backs  up  into  the  elevator  head,  causing 
the  grain  to  back-flow  into  the  boot.  This  is  one  of  the  common 
causes  of  elevator  choke-ups,  especially  in  country  elevators.  The 
average  country  elevator  is  run  by  one  man  and  he  does  not  get 
Up  to  the  top  of  his  house  as  often  as  might  be  expected.  Con- 
sequently he  is  not  always  familiar  with  the  amount  of  grain  in 
the  bins.  Me  invariably  is  very  busy  and  sometimes  these  bins 
In  come  filled  up.  The  spout  leading  t<»  same  fills  up  and  event- 
ually the  grain  starts  to  run  down  the  elevator  leg  and  a  choke- 
up  occurs.  There  are  two  ways  for  eliminating  these  occurrences 
The  first  is  by  putting  in  a  bin  alarm  system.  This  consist-  of 
a  device  which  is  attached  to  the  top  of  the  bin.  When  the  bin 
becomes  tilled  with  grain  this  device  automatically  gives  a  signal 
warning.     It  is  operated  1>\  electricity  and  the  warning  is  given 

by    the    ringing    of    a    hell    on    the    work    floor.      Another    way    to 

overcome  a  choke-up  is  1>\  placing  what  is  called  a  signaling 
distributor  on  tin-  spout  which  leads  to  the  bin.  As  the  -p(»nt 
fills  up  it  chokes  hack  into  the  distributor,  or,  in  other  words,  an 

28 


overflow  device.  This  overflow  may  be  emptied  to  a  floor  or  any 
suitable  receptacle.  The  operator  can  easily  see  this  falling 
grain  in  most  any  part  of  the  work  floor,  or  hear  it  rattling  down 
the  tube,  when  he  immediately  shuts  off  the  grain  and  the  flow- 
age  stops.  He  then  shifts  the  spout  to  another  bin.  Various 
turn-heads  or  overflow  signaling  devices  are  on  the  market,  all 
of  which  are  working  to  a  fairly  satisfactory  degree. 

Sometimes  the  return  spout,  the  non-chokable  head,  is  run 
into  a  relief  chamber.  When  the  bin  is  full  the  return  spout  dis- 
charges into  the  relief  chamber  which  fills  to  the  point  where  the 
downward  pressure  equals  the  sidewise  pressure  in  the  supplv 
spouts,  thereby  shutting  off  the  supply  of  grain.  This  feed  will 
handle  any  kind  of  grain  and  prevent  chokes  from  over-feeding. 

Another  automatic  shut-off  for  an  elevator  leg  is  also  in  use. 
When  the  spout  at  the  head  of  the  elevator  has  filled  to  an  over- 
flow, the  grain  then  runs  down  into  the  balance  cylinder.  The 
weight  of  the  grain  bears  this  cylinder  down  and  automatically 
closes  the  gate  in  the  elevator  boot,  thus  stopping  the  flow  of  ma- 
terial into  the  elevator.  An  electric  signaling  device  is  sometime- 
attached  so  that  a  bell  rings  when  this  cylinder  becomes  filled 
and  moves  its  normal  position. 

Sometimes  sudden  shut-downs  in  elevator  legs  occur.  This 
happens  when  the  cups  are  full  of  grain.  This  results  in  a 
choke-up,  back-legging  causing  it.  that  is.  the  belt  starts  to  drop 
down  instead  of  going  up.  Back-stop  devices  have  been  brought 
out  which  operate  automatically,  immediately  acting  as  a  brake 
on  the  head  pulley  when  it  starts  to  revolve  opposite  to  the  way 
it  is  supposed  to  run.  This  is  simply  an  automatic  brake  devi 
Various  kinds  are  used  and  arrangements  of  this  kind  should  be 
encouraged,  a-  choke-ups  are  caused  frequently,  especially  on 
electrically-driven  legs,  by  what  1-  known  as  hack-legging. 

It  appear^  that  more  research  work  should  he  done  along  the 
Hues  of  providing  better  equipment  For  the  prevention  of  choke- 
ups  in  elevator  legs.    The  average  house  today  takes  no  precau- 
tion  for  such  occurrences.      The  elevator  contra  ind  con 
struction  companies  pay  little  heed  to  devices  of  this  nature,  and 

it  appears  that    some   work  could  he  done   whereby  these  various 

concerns  and  engineers  could  get  together  and  form  s,>me  kind 
of  a  standard  code  with  reference  to  equipment  of  this  nature. 

Mr.  PRICE     Ihis  subject  1-  a  most  important  one  sin 
large  number  of  explosions  have  occurred  from  "choke-ups"  in 

elevat'  \T  1' 


Mr.  DEDRICK — The  point  brought  up  by  Mr.  Brady  in 
regard  to  the  choking  of  elevators  is  one  in  which  I  am  very 
much  interested.  An  elevator  can  be  choked  down  gradually  as 
the  result  of  a  poorly  constructed  or  defective  elevator  head 
discharge,  or  when  by  reason  of  too  great  a  speed,  the  grain  is 
discharged  or  thrown  with  such  force  that  it  strikes  the  forward 
end  of  the  head,  rebounds,  and  falls  down  the  back  leg. 

A  certain  quantity  of  grain  thus  keeps  returning  over  and 
over  all  the  time  the  elevator  is  in  operation,  and  in  the  course 
of  an  hour  or  two  will  become  gradually  overloaded  and  then 
choke  down,  unless  the  grain  from  the  intake  spout  is  shut  off 
to  relieve  and  allow  the  elevator  to  clear  itself. 

I  have  had  elevators  choked  down  simply  by  strings  lodging 
on  the  tongue  (a  projection  above  the  throat  or  discharge  and 
between  it  and  the  back  leg).  They  piled  up  so  high  that  a  stream 
of  grain  or  other  stock,  discharged  from  the  cups,  would  not 
wholly  clear  this  obstruction  and,  meeting  with  this  obstruction, 
would  fall  down  the  back  leg. 

AYhen  at  such  times  grain  or  any  other  material  falls  down 
the  back  leg  it  induces  air  pressure  within  the  leg  and  causes 
what  is  called  "blowing,"  producing  a  great  deal  of  dust  which 
is  emitted  from  any  opening  in  elevators,  spouts,  etc.  This 
"blowing"  serves  notice  that  something  is  wrong  and  that  there 
is  danger  of  a  possible  choke  and  stoppage  of  the  elevator  belt. 
The  point  of  discharge,  that  is  the  throat,  may  be  too  high  and 
i  ause  more  or  less  trouble  and  choking  down. 

1  have  had  a  few  cases  where  I  was  called  in  to  rectify  the 
matter  and  found  the  throat  was  up  so  high  that  the  grain  would 
not  discharge  properly;  that  so  much  grain  would  go  down  the 
back  leg  that  perhaps  in  a  half-hour's  time  or  even  less,  the 
elevator  would  be  choked  down,  unless  relieved  in  time  to  avoid 
it,  and  then  allowing  the  elevator  to  clear.  The  method  of  re- 
lieving the  elevator  and  preventing  a  choke  down  when  the  dis- 
charge spout  is  filled  or  clogged  Up  at  the  head,  by  allowing  the 
grain  to  flow  down  a  spout  the  opening  of  which  is  above  the 
clogged  point,  and  this  relief  spout   led  to  a  point  into  the  intake 

>pou1  at  bool  and  just  ahead  of  it,  so  that  the  returning  grain 

will    flow    in   ahead  and   eut   off   the   original    feed,    thus   allowing 

tli<'  returned  -rain  to  make  the  round  over  and  over  until  the  clog 

at    head    is  cleared,   is    very   good   indeed.      However.    [    think    the 
besl    method    is   to  have  an   automatic  arrangement    in    which   the 

feed  is  eut  off  entirely,  thai  is,  the  grain  from  the  release  spout  at 

the   head   flowing    into  a    receptacle  or   pivoted   box    that    under   a 

30 


given  load  or  weight  will  operate  a  lever  or  series  of  levers  con- 
nected to  the  slide  of  intake  spout  and  close  it,  allowing  the  ele- 
vator to  clear  itself  of  all  grain,  the  box  being  large  enough  to 
accommodate  the  excess  grain.  I  think  slides  could  be  thus  ar- 
ranged to  be  closed  automatically  the  same  way,  whether  the 
grain  is  led  into  the  boot  at  front,  back  or  side. 

The  choking  down  of  an  elevator  is,  I  think,  one  of  the  most 
dangerous  features  for  causing  fires  and  possible  explosions  in 
a  grain  elevator,  flour  mill,  or  any  cereal  plant.  I  know  of  a 
number  of  cases  where  the  choking  down  of  the  elevator  has 
started  fires. 

Mr.  PRICE — Now  you  men  have  been  in  many  plants  the 
last  few  years,  and  I  am  very  desirous  to  know  if  you  have  been 
in  plants  where  they  have  installed  any  of  these  devices,  or  some- 
thing similar.  If  so,  which  is  giving  the  best  results  that  could 
be  obtained  in  connection  with  choke-up  troubles. 

Mr.  WITMER — In  the  new  Pennsylvania  Railroad  elevator 
at  Baltimore,  which  is  under  construction  and  not  yet  in  com- 
plete operation,  they  have  a  device  installed  which  is  supposed 
to  take  care  of  the  elevator  going  back,  or  a  back  stop.  The 
elevator  has  not  as  yet  been  tried  out  sufficiently  to  say  whether 
it  will  work  successfully  or  not.  They  have  only  run  about 
100,000  bushels  of  grain  in  order  to  try  out  the  machines-  I  have 
been  told  that  when  this  plant  is  completed  it  will  not  only  be 
the  largest  grain  elevator  on  the  eastern  coast,  but  will  have 
the  latest  and  best  equipment  obtainable.  In  other  words,  the  last 
word  in  elevator  construction. 

Mr.  HIBBARD — In  the  new  plants  that  are  built  in  the  west 
they  have  separate  motors,  and  when  a  choke  occurs  in  the  eleva- 
tor it  breaks  a  circuit  and  throws  the  motor  off. 

Mr.  PRICE-  We  understand  the  Public  Elevator  at  New  Or- 
leans has  been  using  a  device  of  this  nature. 

Mr.  BRt  >\YX — I  do  not  recommend  this  installation  at  this 
time,  i  understand  from  Mr.  San  ford,  the  superintendent,  that  it 
is  his  own  invention  and  he  is  endeavoring  to  gel  a  patent  on  it. 
I  ran  give  you  a  brief  description  of  the  system.  The  eleval 
is  run  b)  one  motor  and  the  conveyor  carrying  grain  to  the  eleva- 
tor is  run  by  a  separate  motor.  An  idler  pulley  on  the  elevator 
bell  is  connected  to  a  steam  engine  governor.  In  case  of  a  choke, 
the  elevator  belt  slows  down;  at  the  same  time  the  governor 
drops  and  breaks  the  circuit  to  the  motor  running  the  conveyor 
which  carries  the  grain  to  the  boot  of  the  elevator.    In  this  w; 

31 


before  the  elevator  belt  has  had  a  chance  to  stop  or  choke,  the 
grain  being  carried  to  the  boot  is  stopped  and  prevents  the  boot 
being  filled.  This  elevator  also  has  a  stop  at  the  top  to  prevent 
the  buckets  running  down  and  carrying  grain  back  to  the  boot. 
As  soon  as  the  trouble  has  been  remedied,  the  elevator  is  started 
again.  In  fact,  it  must  be  started  before  this  automatic  contact 
is  thrown  in  by  the  governor.  As  soon  as  the  elevator  is  again 
in  operation,  the  belt  conveyor  can  be  started  and  the  grain  ele- 
vation continued  as  before.  I  do  not  know  whether  I  have  made 
myself  clear  on  this  matter.  This  installation,  I  believe,  is  the 
only  satisfactory  installation  that  I  know  of  in  the  country  and 
is  fool-proof. 

Mr.  RILEY — In  regard  to  the  non-chokable  leg  mentioned  by 
Mr.  Brady,  I  wish  to  state  that  I  visited  this  plant  and  saw  this 
leg  in  operation  and  I  understand  that  it  has  been  in  use  for 
some  time  and  is  giving  satisfaction.  Housed  in  at  the  back  of 
the  leg,  just  below  the  spout  leading  from  head  of  leg,  is  a  metal 
bucket  held  in  position  by  a  weight  or  counter-balance  attached 
to  bucket  by  a  short  piece  of  bell-cord,  this  cord  passing  over  a 
small  pulley  placed  at  one  side  of  leg.  This  weight  or  counter- 
balance exceeds  the  weight  of  the  bucket  by  fifteen  pounds.  The 
bucket  is  attached  by  steel  cable  to  tension  pulley  of  belt  drive, 
driving  screw  conveyors  that  convey  grain  to  leg.  If  the  bin  that 
leg  is  discharging  grain  to  becomes  filled,  and  grain  flows  back 
into  leg  from  spout  leading  to  bin,  this  bucket  receives  it  and 
as  soon  as  weight  of  grain  in  bucket  exceeds  weight  of  counter- 
balance, bucket  drops  down  and  automatically  draws  tension  pul- 
ley away  from  driving  belt  of  screw  conveyor  that  conveys  grain 
to  leg,  allowing  driving  belt  to  slack  and  thereby  stopping  con- 
veyor. Stopping  of  conveyor  automatically  shuts  off  flow  o/ 
grain  from  spouts  leading  into  conveyor,  as  these  spouts  lead 
into  the  side  of  the  conveyor  instead  of  to  the  top  as  we  usually 
find  them.  The  capacity  of  this  bucket  is  approximately  600 
pounds  of  grain  and  this  grain  passes  out  through  a  three-inch 
hole  in  the  bottom  of  bucket  where  it  falls  into  leg  and  is  carried 
to  head  of  leg  where  it  again  falls  into  bucket  and  this  continues 
until  spout  is  set  for  another  bin,  when  grain  in  bucket  and  leg 
Is  discharged  into  il  and  buckel  automatically  resumes  its  normal 
position. 

Mi'.  PRICE  Mr.  Riley  sent  a  report  to  Washington  regard- 
ing this  installation   and   we    felt   that   it   was  giving  satisfactory 

results. 


Dr.  BROWN — Whenever  we  get  a  choke  in  an  elevator,  we 
get  friction  at  the  head,  and  I  should  like  the  opinion  of  some 
one  as  to  the  practicability  or  effectiveness  of  sprinkler  heads  in 
elevator  heads  to  extinguish  the  fire,  or  to  prevent  excess  heat- 
ing which  may  result  from  a  choke. 

Mr.  HIBBARD— It  takes  about  170  degrees  Fahrenheit  to 
open  a  sprinkler  head,  and  by  that  time  the  whole  plant  would 
be  on  fire.  The  sprinkler  head,  as  a  rule,  is  set  out  at  a  side 
with  an  opening  between.     It  is  not  directly  over  the  pulley. 

Dr.  DUVEL — Wrould  it  not  be  possible  to  provide  elevator 
heads  with  a  thermo-couple  adjusted  so  that  when  the  tempera- 
ture resulting  from  friction  approached  the  danger  point,  the 
elevator  would  be  stopped  automatically.  Such  a  device  could 
probably  be  used  in  connection  with  or  as  a  supplement  to  sprink- 
ler heads.  I  appreciate  that  elevator  foremen,  in  case  of  a  choke. 
are  frequently  inclined  to  force  the  machinery  in  order  to  relieve 
the  choke,  but  I  believe  in  most  instances,  if  they  can  be  made  to 
fully  appreciate  the  hazard  surrounding  such  procedure,  they 
would  prefer  to  stop  the  elevator  and  remove  the  cause  of  the 
choke  rather  than  to  take  the  chance  of  an  explosion.  This,  of 
course,  involves  a  long  and  tedious  process  of  education. 

Mr.  HIBBARD — The  sprinkler  head  has  to  be  out  of  the 
way  because  if  it  comes  in  contact  with  the  buckets  it  is  likely  to 
be  broken  open  and  flood  the  leg.  That  is  why  they  set  it  out  to 
the  side  with  an  opening  into  the  elevator  head. 

Dr.  BROWN — You  can  set  it  directly  above  the  pulley,  I 
believe. 

Mr.  McCOLLAM — In  this  connection  1  might  call  your  at- 
tention to  an  installation  in  California.  It  seemed  a  very  clean 
installation  when  it  came  to  put  out  a  fire,  You  might  call  them 
gas    heads;    that    is.   carbon    dioxide    tank-    were    attached    to    the 

elevator  head.  In  case  of  fire  the  fusible  heads  were  melted  and 
the  carbon  dioxide  flowed  into  the  elevators  and.  of  course,  set- 
tled, being  heavier  than  air,  and  put  out   the  tire. 

Mr.  PRK  E  The  Pacific  I  oasl  ha-  evidentl)  tried  tin-  use  of 
inert  gases  very  effecth  ely. 


33 


"A  DISCUSSION  OF  THE  RELATION  OF  GRAIN  DUST 

EXPLOSIONS   AS   APPLIED   TO    FLAT-WARE- 
HOUSES  AND   ELEVATORS." 

By  George  P.  Bodxar. 

I  will  try  to  tell  as  briefly  as  possible  the  relation  between 
Flat-warehouses  and  Elevators  with  respect  to  Grain  Dust  Ex- 
plosions as  these  types  of  grain  handling  houses  appear  to  me 
from  personal  observation. 

In  the  Pacific  Northwest  I  had  occasion  to  visit  many  Flat- 
warehouses  that  handled  flour  and  grain  stocks  of  the  U.  S.  Grain 
Corporation.  Most  of  the  warehouses  had  cleaning-houses 
equipped  with  about  the  same  type  of  cleaning  machinery  that  is 
found  in  the  ordinary  elevator  so  that  similar  conditions  prevailed 
in  the  former  as  were  found  in  the  latter  kind  of  grain  handling 
plant. 

In  warehouses  without  any  grain  handling  or  cleaning  ma- 
chinery, which  fact  implies  the  creation  of  very  little  or  no  dust 
as  compared  to  the  elevator,  it  seems  to  me  that  the  chances  of  a 
dust  explosion  are  very  slight  or  remote.  In  case  of  a  serious  fire, 
a  warehouse  of  the  above  type,  handling  flour,  would  have  an 
explosion  risk  where  one  handling  grain  alone  would  not.  The 
bursting  of  flour  sacks  piled  as  high  as  they  are  (have  seen  them 
as  high  as  13  feet  at  least)  could  very  easily  cause  heavy  dust 
clouds  with  the  resultant  explosion  risk.  The  bursting  of  grain 
sacks  under  similar  fire  conditions  would  be  unlikely  to  create 
enough  dust  for  an  explosion. 

The  cleaning  section  of  the  plants  visited  was  usually  found  in 
about  the  center  of  the  warehouse.  The  machinery,  elevator  legs, 
spouts,  etc.,  are  more  or  less  exposed  to  the  interior  of  the  ware- 
house so  that  in  walking  through  the  warehouse  much  of  the 
machinery  is  visible.  It  is  the  desire  to  consider  these  types  of 
warehouses  with  respect  to  the  following  feature,  that  is,  the 
amount  of  exposure  of  cleaning  house  above  the  top  of  the  ware- 
house proper.  The  cleaning  section  of  the  first  type  is  so  open 
with  respect  to  the  interior  of  the  warehouse  that  even  though 
there  is  a  sufficienl  quantity  of  dust  accumulated  on  the  spouts 

and  other  ledges  to  propagate  an  explosion,  the  explosion  could 

hardly  do  much  damage  in  so  far  as  the  demolishing  and  hurling 
of  material  by  the  force  of  the  explosion  is  concerned,  as  would 

be  the  ease  were  the  machinery  enclosed  tO  tin-  extent   it   is  in  an 

elevator. 

The  remarks  made  with  reference  to  this  cleaning  house  will 

34 


apply  with  equal  force  to  the  portions  of  the  cleaning  houses  in 
the  other  two  types  that  are  below  the  roof  of  the  warehouse 
proper  and  exposed  to  the  interior  of  the  warehouse.  So  far  as 
an  explosion  is  concerned  about  the  same  thing  would  happen  in 
the  parts  of  the  cleaning  houses  above  the  roof  of  the  warehouses 
as  would  happen  in  the  ordinary  wooden  elevator  that  was  dusty 
or  had  dust  accumulations  to  propagate  an  explosion. 

The  cleaning  house  in  the  first  type  is  not  equipped  with  bins 
such  as  are  found  in  the  wooden  or  concrete  elevator.  The  other 
two  cleaning  houses  are  equipped  to  handle  or  store  grain  in 
bulk  on  a  small  scale,  (up  to  about  10,000  bu.)  that  is,  grain 
received  in  sacks,  after  being  cleaned,  is  held  in  storage  for 
short  periods.  The  arrangement  for  discharging  the  grain  into 
the  bins  is  the  same  as  that  of  the  elevator.  Ordinarily  the  grain 
is  resacked  as  fast  as  it  is  cleaned.  When  this  is  not  the  case  the  bins 
are  used  and  there  is  therefore  the  same  danger  of  an  explosion  in 
the  bins  of  the  cleaning  house  as  there  is  in  the  bins  of  the 
elevator. 

With  reSpect  to  the  bins  and  choke-ups  in  the  elevators  the 
same  precautions  therefore  apply  for  prevention  of  dust  ex- 
plosions as  apply  to  the  elevator.  With  those  we  are  familiar, 
so  there  is  no  need  mentioning  them  at  this  time. 

The  cleaning  section  of  the  warehouses  visited  was  rarely  as 
high  as  the  country  wooden  or  concrete  elevator  of  about  forty  or 
fifty  thousand  bushels  capacity,  and  no  manlifts  such  as  are  com- 
mon in  elevators  were  found.  Consequently  they  have  nothing 
that  resembles  that  part  of  the  elevator  commonly  termed  the 
"well."  Any  explosion  occurring  in  the  bottom  of  the  cleaning 
house  could  not  travel  up  through  a  "well"  as  was  apparently 
the  case  in  a  recent  explosion  in  the  Middle  West.  In  my  \  isit  ^ 
to  elevators  it  was  not  unusual  to  find  the  "wells"  of  elevators 
pretty  dusty  compared  to  other  parts  of  the  plants.  In  case  of  the 
cleaning-house  of  the  flat-warehouse  it  is  therefore  an  advantage 
to  have  no  "well"  in  which  dust  can  accumulate  to  produce  an 
explosion  hazard. 

A  tire  originating  from  a  dust  explosion  (or  from  any  other 
Cause  i  in  the  \  icinity  of  the  elevator  heads  is  more  easily,  or  rather 

more  safely  reached  in  the  case  of  the  cleaning  house  than  in  the 
case  of  the  grain  elevator.     The  stairways  of  the   former  are 

arranged   in   tin-  order   they   are   in   a   flour  mill   of  about   two  or 

three  hundred  banal-  capacity.  In  quite  a  number  oi  the  eleval 

visited  1  heard  operators  declare  that  if  a  tire  e\er  Mai  ted  m  the 
cupola  of  their  elevator,  the   fad   that  then-   was  a   sutTieient    tire 

3S 


equipment  in  the  top  of  the  elevator,  would  not  be  an  inducement 
to  go  up  the  manlift  to  the  top  to  extinguish  the  fire.  The  ob- 
jection seems  to  be  the  fact  that  the  manlift  is  ordinarily  sup- 
ported by  means  of  a  fibre  rope.  The  flash  of  a  dust  explosion 
could  very  easily  ignite  the  rope  and  it  would  be  consequently 
quite  hazardous  to  attempt  to  put  a  fire  out  in  the  top  of  the 
elevator.  A  fire  starting  from  a  source  other  than  a  dust  ex- 
plosion would  naturally  create  the  same  condition  but  probably 
not  as  quickly,  depending  upon  the  circumstances. 

From  the  standpoint  considered  the  elevator  is  therefore  not 
as  desirable  as  the  cleaning  house  of  the  flat-warehouse.  A 
suggestion  pertinent  here  is:  Equip  elevators  with  the  manlifts 
braced  with  metal  and  then  supported  by  steel  cables  instead  of 
fibre  rope. 

With  one  exception  the  cleaning  houses  in  the  flat-warehouses 
of  the  Northwest  were  much  cleaner  with  respect  to  dust  than 
either  the  wooden  or  concrete  elevators  taken  as  a  whole,  and 
consequently  the  explosion  hazard  was  less,  and  will  continue 
so  providing  the  above  condition  remains  true. 

The  points  brought  out  in  the  above  discussion  are  about  as 
follows : 

1.  On  account  of  the  open  style  of  construction  of  the 
section  of  the  cleaning  houses  beneath  the  roof  of  the  ware- 
house proper  an  explosion  in  the  cleaning  house  at  this  floor  would 
not  result  in  as  much  direct  damage  from  the  explosion  as  would 
be  the  case  in  an  elevator. 

2.  Flat-warehouses  of  the  type  found  in  the  Northwest  have 
the  same  danger  of  dust  explosions  in  elevator  heads,  bins,  and 
upper  floors  as  the  wooden  or  concrete  elevator  (when  the  clean- 
ing houses  are  equipped  with  bins). 

3.  On  account  of  the  fact  that  the  cleaning  houses  of  ware- 
houses have  no  "wells"  common  to  elevators,  explosions  occurring 
in  the-  former  on  any  floor  have  no  easy  access  to  other  floors, 
except  through  elevators  and  stairways  if  these  are  not  closed  by 
doors. 

4.  On  account  of  the  use  of  manlifts  supported  by  fibre 
ropes  the  elevators  presenl  more  danger  when  it  comes  to  putting 
out  fires  in  the  cupola  of  the  elevator  than  do  the  cleaning  houses 
with   fire  at   a   similar  point. 

Mi-.    PRK   E      Merc  is  a  chance  to   find  out   something  about 

the  Pacific  Northwest  Arc  there  any  questions  you  would  like 
t(»  ask  Mr.  Bodnar? 

36 


Dr.  DUVEL — If  the  elevator  managers  are  aware  of  this 
danger  I  would  think  they  would  use  a  wire  cable  on  the  manlift 
or  elevator  instead  of  ordinary  rope. 

Mr.  BODNAR — I  have  seen  that  arrangement  in  two  ele- 
vators in  Idaho.  In  the  elevator  at  Moscow,  Idaho,  the  man- 
lift  is  equipped  with  a  wire  cable  about  three-eighths  of  an  inch 
in  diameter,  which  is  quite  flexible  and  serves  the  purpose  I  had 
in  mind. 

Dr.  DUVEL — It  seems  to  me  if  they  recognize  they  have 
that  risk  it  would  be  one  of  the  first  things  they  would  take 
care  of. 

Mr.  BODNAR — I  went  into  an  elevator  and  found  a  fire  ex- 
tinguisher on  the  top  floor  only.  It  had  not  been  in  use  for 
years.  The  operator  said  if  they  had  a  fire  in  the  basement  he 
wouldn't  run  up  to  the  top  floor  to  get  the  fire  extinguisher,  or 
in  case  of  a  fire  in  the  cupola  he  would  not  go  up  to  attempt  to 
put  the  fire  out. 

Dr.  DUVEL — I  suppose  that  was  for  the  benefit  of  the  in- 
surance company? 

Mr.  PRICE — Are  there  any  further  questions  on  the  dis- 
cussion of  the  flat-warehouse  matter? 

Mr.  REED — I  would  like  to  ask  a  question.  Are  the  cars 
loaded  by  means  of  sacks  or  is  the  grain  shipped  in  bulk? 

Mr.  BODNAR — The  grain  is  shipped  in  bulk  and  sacks  to 
the  mills  on  the  coast  and  is  ground  there-  The  coast  is  learning 
to  handle  grain  in  bulk  more  and  more  than  it  has  been  doing, 
and  it  is  just  a  question  of  time  when  they  will  not  handle  any 
more  in  sacks.  In  my  recent  visits  to  the  country  I  noticed  many 
new  concrete  elevators  in  the  course  of  construction.  These  cer- 
tainly are  signs  of  the  breaking  away  from  sack  handling  of 
grain  in  favor  of  the  bulk  method. 

"EXPERIENCES    THAT    HAVE    BEEN     HELPFUL    L\ 
MAKING  INSPECTIONS." 

By  Mr.  ( i.  A.  I  [ibbabd. 

In  making  inspections  of  the  mills  and  elevators  in  Wisconsin, 

Illinois,    Michigan,    Indiana   and    parts    of    Kentucky    it   has   been 

my  fortune  to  come  in  contact  with  varied  types  of  managi 
and  superintendents.    Some  of  these  were  very  skeptical,  es] 

dally  the  man  who  has  been  in  the  business   tor  a  great   number 


of  years  and  having  no  accidents.  The  other  class  were  those 
who,  having  read  about  the  dangers  from  dust  explosions,  were 
anxious  to  co-operate  in  every  way  possible  to  prevent  them. 

It  is  with  the  first  class  of  men,  or  the  skeptical  ones,  where 
I  have  received  the  most  opposition,  that  I  have  been  able  to 
accomplish  the  most  good.  The  same  has  been  true  in  my  own 
case,  as  I  was  keen  to  see  any  defects  or  conditions  in  the  plant 
to  prove  my  argument  and  bring  home  to  the  operator  the  seri- 
ous condition  that  existed. 

I  have  in  mind  one  superintendent  of  a  large  elevator  in  par- 
ticular in  Chicago,  who  has  been  in  the  business  practically  all 
his  life  and  was  pensioned  by  the  operator,  but  is  still  handling 
one  of  their  elevators.  When  I  made  my  first  visit  to  the  plant, 
while  giving  a  demonstration  of  a  small  explosion  and  a  short 
talk  to  the  men,  the  superintendent  did  not  regard  the  dust  situa- 
tion as  serious.  He  showed  me  every  courtesy  possible.  It  was 
not  until  after  the  explosion  at  the  Murray  elevator  in  Kansas 
City,  when  I  returned  to  this  same  party  and  was  giving  him  a 
few  details  of  the  explosion  and  showing  him  a  few  photographs 
of  the  destruction  wrought  by  the  explosion,  that  he  finally 
acknowledged  the  dangers  existing  from  an  accumulation  of  dust. 
In  order  to  withdraw  gracefully  from  the  argument,  he  wanted 
me  to  understand  that  he  had  reference  to  an  explosion  caused 
by  spontaneous  combustion  in  the  dust,  which  we  know  is  im- 
possible. 

The  most  helpful  experience  that  I  have  had  was  that  fol- 
lowing the  explosion  at  a  feed  plant  and  elevator  in  Milwaukee, 
Wis.,  in  May  of  1919.  It  was  a  disastrous  explosion,  killing 
three  men,  injuring  four,  and  causing  a  property  loss  of  about 
one  hundred  and  fifty  thousand  dollars. 

The  management  thought  that  after  erecting  a  concrete  and 
steel  plant  they  had  taken  all  precautions  necessary  for  their 
employees'  safety  as  well  as  their  own.  They  had  overlooked 
the  explosion  hazard  and  had  no  appliances  or  system  to  take 
care  of  the  removal  of  dust  created  in  the  handling  of  grain  and 
feed  materials  in  their  plant.  It  was  while  1  was  making  the 
investigation  of  this  explosion  that  the  management  came  to  me 
and  made  the  request  that  when  the  plant  was  rebuilt  they  would 
appreciate  any  help  that  we  might  he  able  to  give  them.    Several 

months  later  they  notified  me  that  they  were  about  ready  to  re- 
build and  desired  to  have  me  make  recommendations  as  to  the 

points   at    which    Miction    should    he    applied    and    other    explosion 

preventive  measures  to  he  used.    These  requests  were  complied 

38 


with  and  suction  was  applied  to  the  elevator  boots,  elevator 
heads  and  to  an  expansion  chamber  on  the  screw  conveyor  which 
received  material  from  the  attrition  mill.  The  other  safety  meas- 
ures installed  were  a  choke  valve  in  the  screw  conveyor  hold- 
ing back  a  certain  amount  of  material  at  all  times  to  prevent  the 
spread  of  any  explosion  that  might  occur  in  the  attrition  mill  or 
other  parts  of  the  system,  and  a  release  pipe  leading  direct  from 
the  screw  conveyor  to  the  outside  to  relieve  any  pressure  that 
might  be  created  by  an  explosion  in  the  system. 

About  thirty  days  after  this  equipment  had  been  installed 
an  inspection  of  the  plant  was  made  and  it  was  found  in  the 
very  best  of  condition ;  the  suction  system  was  collecting  approxi- 
mately eight  grain  sacks  of  dust  and  fine  material  per  day,  which, 
without  the  suction  system,  would  have  been  scattered  through- 
out the  plant  creating  a  dangerous  condition  and  requiring  con- 
siderable labor.  Where  we  find  a  dusty  condition  existing  in  a 
plant  it  is  usually  laid  to  the  scarcity  of  help. 

One  other  experience  noted  in  a  Chicago  elevator  helps  to 
prove  that  a  dust  free  elevator  or  plant  is  practically  explosion 
proof.  It  was  in  the  evening  just  following  the  closing  down  of 
the  plant  when  fire  was  discovered  on  the  distributing  floor  of 
the  elevator.  An  alarm  was  turned  in  and  on  the  arrival  of  the 
fire  department  the  fire  was  quickly  extinguished  with  a  very 
small  fire  damage.  Upon  investigation  it  was  found  that  the 
fire  originated  from  an  overheated  bearing  on  one  of  the  rollers 
underneath  the  distributing  belt.  It  was  communicated  to  a 
wooden  frame  work  and  from  there  to  the  cleaning  machine, 
which  was  mostly  destroyed  by  fire.  Previous  inspections  showed 
this  plant  to  be  in  very  good  condition  and  it  is  probably  due 
to  this  fact  that  there  were-  no  explosions  causing  heavy  losses. 

Mr-  PRICE — It  may  be  that  the  men  who  have  made  inspec- 
tions have  had  experiences  somewhat  similar  to  those  referred 
to  by  Mr.  Hibbard  and  we  have  sufficient  time   for  discussion 

of  this  subject,  or  any  other  subject  taken  up  this  afternoon. 

Dr.  BAILEY — 1  take  it  as  the  consensus  of  opinion  that 
when  a  series  of  bins  occur  in  a  plant  it  is  advisable  to  cover  the 

bins  and  vent  them  through  the  roof   with  a   steel  or  galvanic 

iron  vent  suitably  capped. 

Dr.    1JROWN—  I   made  that   suggestion  at    i  home. 

Mr.  Mc(  OLLAM     May  1  add  thai  it  seems  to  be  the 
eral  tendency  in  modem  elevator  construction,  i  I  have 

39 


observed,  to  use  natural  ventilation  as  far  as  possible?  I  will 
call  your  attention  again  to  the  elevator  in  Ogden  which  has  no 
dust-collecting  system  to  speak  of  at  all.  The  garner  and  scale 
hopper  are  both  vented  by  means  of  a  very  large  vent  to  the 
open  air.     This  is  supposed  to  take  care  of  the  dust  hazard. 

Dr.  BAILEY — Each  one  of  these  bins  should  have  its  own 
distinct  vent. 

Mr.  HELMKAMP — I  have  run  across  some  elevators  in 
which  the  conveying  belts  seem  to  be  pretty  close  to  the  floor. 
It  would  seem  that  if  they  would  raise  these  belts  possibly  six 
inches  it  would  be  easier  to  sweep  out  and  this  change  would 
not  incur  much  additional  expense. 

Mr.  DEDRICK — The  venting  idea  is  good.  I  think  the  same 
results  could  be  accomplished  by  a  suction  system  and  dust  kept 
within  certain  limits  and  from  getting  out  of  machines,  spouts, 
elevators  and  other  openings-  The  suction  would  pull  the  dust 
out  and  away  from  bins,  elevators,  etc.,  at  once,  without  allow- 
ing it  to  float  within  the  building.  The  fan  drawing  the  dust 
should  exhaust  into  dust  collectors,  preferably  outside  the  build- 
ing. 

There  should  be  direct  suction  at  every  point  where,  in  the 
course  of  operation,  dust  is  made,  and  liable  to  escape  and  to 
spread  throughout  the  plant.  For  instance,  I  would  carry  a  suc- 
tion trunk  with  a  hood  right  up  to  the  car  door  and  over  the 
dump  grating.  This  would  take  a  great  deal  of  dust  right  at  that 
point,  and  leave  that  much  less  to  be  contended  with  after  the 
grain  entry  in  the  elevator  or  mill.  In  the  ordinary  elevator 
much  of  the  dust  made  at  the  unloading  chute  blows  into  or 
•  ntcrs  the  building. 

This  can  be  accomplished  by  having  just  enough  suction  to 
pull  nothing  but  the  light  floating  dust  away  and  keep  it  mov- 
ing toward  the  hood.  The  elevator  heads  might  be  built  higher 
beyond  the  circle  described  by  the  moving  belt  and  cups,  and 
there  at  the  top,  at  discharge  end,  instead  of  the  ordinary  suction 
-pout  with  its  small  opening,  have  the  suction  spout  opening  ex- 
tend the  full  width  of  top  and  back  a  ways.  This  could  be 
accomplished  by  flaring  the  spout  so  as  to  cover  this  opening. 
This  would  give  more  Spread  or  surface  to  the  drawing  current, 
at  the  same  time  weakening  it  so  that  it  would  be  less  liable  to 
draw  good  material  with  the  dust,  as  happens  with  a  small  open- 
ing with  a  concentrated  current  that  draws  more  heavily  at  the 
point  where  the  grain  is  discharged  as  the  belt  and  cups  move 

40 


over  the  head  pulley.  To  avoid  any  possibility  of  good  grain 
or  material  being  drawn  up,  baffles  may  be  placed  inside  the 
elevator  head  below  the  suction  spout  opening  and  the  discharged 
grain  thrown  in  a  spray,  thus  preventing  a  direct  current  acting 
on  the  grain. 

At  the  trip  is  another  source  of  much  dust.  This  dust  can 
be  taken  care  of  by  placing  a  suction  hood  over  the  point  of 
grain  discharge.  A  suction  trunk  should  extend  the  whole  length 
of  the  elevator  bins  and  tanks.  Stubs  would  allow  of  making 
connection  with  a  trunk  attached  to  the  trip  that  extends  on  both 
sides  of  trip  over  the  bins  on  each  side  of  the  gallery  or  belt 
carrier.  To  the  ends  of  the  trunk,  hoods  (inverted  cones)  could 
be  attached,  one  on  each  side  of  trip.  These  hoods  need  be  only 
part  size  of  the  open  bin,  but  placed  somewhat  above  the  open 
bins.  The  suction  current  should  be  strong  enough  to  draw  the 
dust  as  it  arises  from  the  bin  when  being  filled,  and  thus  keep 
the  dust  within  that  zone  or  area  until  it  reaches  the  hood. 

This  idea  can  be  carried  out  on  the  working  or  unloading 
floor,  by  having  the  unloading  carriage  movable  like  the  trip, 
with  a  hood  over  it  to  be  attached  to  a  main  suction  trunk  over- 
head, similar  to  the  one  at  the  top.  A  hood  should  be  placed  at 
the  discharge  end  of  belt  also.  Suction  should  be  applied  at  the 
elevator  boot,  between  the  legs.  The  main  thing,  I  think,  is  in 
the  first  place  to  avoid,  if  possible,  the  making  of  dust,  and, 
secondly,  to  remove  such  dust  as  is  made  and  liable  to  escape  and 
float  about  the  building,  as  quickly  as  possible  at  the  various 
points.  It  does  not  make  any  difference  as  to  the  kind  of  build- 
ing construction,  whether  wood.  iron,  steel  or  concrete — dust  is 
a  menace  to  all  alike.  A  concrete  or  steel  constructed  elevator 
or  plant  may  not  burn  down,  but  it  can  be  wrecked  by  a  dust 
explosion  in  the  twinkling  of  an  eye.  It  seems  like  the  height  of 
folly  to  erect  costly  steel  or  concrete  elevator  plants  with  the  one 
idea  of  preventing  destruction  by  tire,  and  then  to  make  no  ade- 
quate- provisi(  n  lor  preventing  the  making  of  dust  or  it--  escape 
into  and  diffusion  all  through  the  plant,  and  thus  having  the 
even  present  possibility  of  a  disastrous  explosion. 

Mr.  BODNAR  In  connection  with  Mr.  Hibbard's  paper, 
l  desire  to  refer  to  tin-  general  cleanliness  of  plants  in  the  North- 
west, 'liny  believe  on  the  Pacific  Coast  that  the  climate  has 
something  to  do  with  preventing  explosions,  inasmuch  a-  they 
have  never  had  any,  hut   I  have  set  off,  in  demonstrating  ex 

plosions,  much  of  their  own  dust,  even   on   e\t;emel\    wet    days, 

-41 


and  I  cannot  see  why  they  feel  that  they  will  never  have  an  ex- 
plosion. In  some  of  the  plants  they  seem  to  be  taking  modern 
precautions,  and  still  they  feel  that  the  climate  is  keeping  them 
from  having  explosions. 

Mr.  PRICE — It  would  be  advisable  for  them  to  adopt  addi- 
tional -precautions.  The  large  number  of  thresher  explosions 
in  that  territory  were  due  to  unusual  climatic  conditions.  This 
would  indicate  the  possibility  of  explosions  in  mills  and  elevators. 

Is  there  is  no  further  discussion,  we  will  adjourn  until  to- 
morrow morning. 


FRIDAY   MORNING  SESSION 

April  23,  1920 

Dr.  J.  W.  T.  Duvel,  Presiding 

Dr.  DUVEL — A  few  years  ago,  if  you  talked  with  mill 
operators  as  to  disturbances  or  dangers  attributed  to  static  elec- 
tricity, they  were  of  the  opinion  that  your  arguments  were  based 
on  some  fanciful  theory.  Conditions  have  changed  very  largely 
in  recent  years.  I  am  sure  I  am  not  overstating  the  situation 
when  I  say  that  this  difference  in  viewpoint  is  due  largely  to  the 
work  that  has  been  done  by  the  Department  of  Agriculture  and 
the  Grain  Corporation  along  dust  explosion  prevention  lines. 

The  first  paper  this  morning  will  give  us  some  definite  in- 
formation on  static  electricity  in  attrition  mills  and  methods  of 
removal,  as  based  on  observations  and  investigations  by  Mr. 
McCollam,  who  has  been  in  charge  of  our  dust  explosion  work  on 
the  Pacific  Coast. 

"STATIC  ELECTRICITY   IN   ATTRITION    MILLS   AND 
METHODS  OF  REMOVAL." 

By  M.  E.  McCollam. 

Mr.  McCOLLAM — Mr.  Chairman:  I  have  been  assigned  the 
subject  "Static  Electricity  in  Attrition  Mills  and  Methods  of 
Removal."  • 

Charges  of  static  electricity  which  may  be  built  up  in  attrition 
mills  arc  of  interest  to  ns  chiefly  :is  a  possible  cause  of  grain 
dust  explosions.  Then-  lias  been  much  doubt  as  to  the  power  of 
static  electrical  discharges  to  ignite  <lust  and  cause  fires  or  ex- 
plosions.  Some  of  the  many  interesting  questions  arising  in  this 
connection  are  heat  and  duration  of  sparking,  leakage,  insulation 
by  some  substances,  such  as  oil  films,  and  humidity  conditions  as 

42 


affecting  a  high  potential  in  an  attrition  mill.  Experimentation 
has  resulted  in  difficulties  being  experienced  in  igniting  dust  with 
static  discharges,  and  no  fires  or  explosions  resulting  from  static 
could  be  obtained  in  an  attrition  mill.  However,  the  experiences 
of  myself,  as  I  will  describe  later  on,  have  pointed  to  quite  a  real 
possibility  of  danger  from  this  type  of  electricity  in  attrition  mills. 
Of  course,  fires  and  explosions  have  taken  place  in  many  attrition 
mills,  but  the  cause  has  been  assigned,  generally,  to  foreign  sub- 
stances going  through  the  mill  and  striking  fire.  Such  materials 
may  be  stones,  nails,  pieces  of  metal,  etc.  Static  electricity  as  a 
cause  has  been  generally  depreciated. 

In  treating  this  phase  of  the  subject,  we  may  say  that  the  ex- 
plosion is  secondary  in  the  case  of  an  attrition  mill,  and  it  is 
usually  the  fire  originating  in  the  mill  which  starts  the  trouble. 
This  fire  spreads  to  dusty  spouts  or  bins  which  are  connected  with 
the  mill  and  an  explosion  occurs.  Sometimes  the  fire  spreads 
rapidly  and  an  explosion  occurs  almost  instantly,  and  at  other 
times  the  fire  smoulders  for  some  little  while,  the  explosions  oc- 
curring later  on.  There  are  three  possible  causes  of  fire  starting 
in  an  attrition  mill.  These  are:  First,  hard  metallic  foreign  sub- 
stances going  through  the  mill  and  striking  sparks ;  Second, 
frictional  heat  caused  by  grinding  certain  materials  may  cause 
combustion  to  start,  especially  under  conditions  of  over-feeding 
if  mill  has  no  vents  to  complete  the  air  circulation ;  Third,  spark- 
ing or  discharge  of  static  electricity  over  an  appreciable  period 
may  ignite  the  product  being  ground  in  an  attrition  mill.  This 
latter  means  is  the  one  with  which  we  are  concerned  most  at 
this  moment.  Most  of  the  static  electricity  in  a  direct  connected 
attrition  mill  is  generated  by  the  action  between  the  grinding 
plates.  It  is  questionable  whether  there  is  any  static  generated 
ai  all  by  the  induction  motors  driving  the  mill.  In  ca<e  of  a 
belt  driven  mill,  there  may  be  quite  an  appreciable  charge  on  the 
bell  building  up  a  potential  in  the  mill. 

For  the  most  part,  it  is  my  intention  to  describe  the  details 
surrounding  a  series  of  seven  explosions  which  took  place  in  an 
attrition  mill  during  the  period  of  one  week  in  the  cereal  mill  of 
the  Sperry  Flour  Company,  .it  Stockton,  California.  Some  of 
these  explosions  occurred  on  the  same  day.  The  most  violent 
explosion  of  the  seven  was  one  which  resulted  in  the  elevator  leg 
to  which  the  mill  was  -pouted  being  damaged.    A  wooden  sa 

vent  at  one  side  of  the  leg  was  blown  off.  as  was  also  the  elevator 

head.     <  Ipinion   was   expressed   that   an   explosion   could   easily 
have  hem  caused  throughout  the  plant  had  it  not  been  clean  and 

43 


free  from  dust  accumulations,  and  this  is  probably  true.  The 
attrition  mill  in  which  the  explosions  occurred  was  ball-bearing 
and  directly  connected  to  induction  motors.  It  was  used  for 
grinding  oat  hulls  expressly.  From  a  huller  the  groats  and  hulls 
fell  to  an  air  blast  which  was  used  to  separate  these  two  products. 
The  hulls  were  blown  over  into  a  chamber  which  was  spouted 
to  the  attrition  mill.  The  groats  being  heavy  fell  by  gravity  into 
a  separate  bin.  The  significance  of  this  is  that  any  heavy  foreign 
substance  would  have  fallen  into  the  bin  with  the  groats  and 
would  not  have  been  carried  over  to  the  attrition  mill.  As  an 
added  protection,  the  mill  had  the  usual  magnetic  separator  before 
it.  The  mill  had  no  choke  conveyor  beneath  it  and  was  spouted 
directly  to  an  elevator.  After  the  first  few  explosions,  the  miller 
assumed  that  since  it  was  practically  impossible  for  any  foreign 
material  to  get  into  the  mill,  the  cause  could  be  traced  to  static 
electricity.  He  took  some  pains  to  prove  his  assumptions,  and 
did  it  very  conclusively  in  his  own  mind.  First,  a  gold-leaf 
electroscope  was  procured  and  various  parts  of  the  particular 
mill  were  tested.  Violent  positive  deflections  were  noticed  when 
parts  of  the  frame  were  touched,  and  none  at  all,  or  what  the 
miller  thought  were  negative  deflections,  when  the  shafting  was 
touched.  What  was  probably  more  convincing  and  certainly 
more  spectacular,  was  the  next  step  taken  by  the  miller.  He  cut 
a  piece  out  of  the  plate  housing  of  the  mill  and  inserted  a  piece 
of  glass  through  which  he  could  watch  the  inside  of  the  mill. 
At  the  instance  of  the  most  violent  explosion,  the  miller  was 
watching  sparks  jumping  from  the  grinding  plates  of  the  mill. 
The  sparking  was  intermittent  at  first  and  then  continuous.  The 
sparks  seemed  to  be  streaming  around  the  outside  edges  of  the 
grinding  plates.  Almost  immediately  after  this  last  occurrence 
the  explosion  took  place  in  the  elevator  leg.  The  miller  partic- 
ularly noticed  the  color  of  the  sparks  or  "fire."  It  was  the  light 
blue,  characteristic  of  static  electricity.  The  miller  was  convinced 
that  the  explosions  were  being  caused  by  static  sparking  in  the 
mill,  and  immediately  took  steps  to  avoid  future  trouble.  Not 
only  this  mill  but  all  the  attrition  mills  in  the  plant  were  grounded 
a-  a  result. 

The  miller,  in  doing  this,   fully  believed  that  all  the  charge 
could  In-  led  off  1>\  simple  attaching  the  ground  wire  to  the  frame 

of  the  attrition   mill.      This  method  was  employed,  and  although 

in  my  opinion  it  is  not  as  desirable  a  wiring  system  as  could  he 

in-tailed,   the    far!    Stands    that    no   mure   trouble    has   been    forth- 
coming in  tin-  plant  since  the  grounding  was  done. 

44 


The  reason  for  the  effectiveness  of  this  grounding  method 
was  due  no  doubt  to  the  fact  that  the  mill  was  a  ball-bearing  one, 
and  it  is  here  that  we  must  turn  to  a  consideration  of  the  relation 
of  types  of  bearings  on  an  attrition  mill  to  the  passage  and  stor- 
ing up  of  static  charges.  Even  though  a  ground  wire  is  led  from 
one  point  of  contact  on  the  frame  of  a  ball-bearing  attrition  mill, 
it  is  possible  that  this  may  suffice  to  lead  off  all  of  the  electricity. 
The  principle  of  lubrication  of  a  ball-bearing  machine  is  entirely 
different  from  that  of  an  ordinary  box-bearing.  There  is  always 
a  certain  point  on  one  of  the  balls  which  is  in  contact  with  both 
the  shaft  and  the  housing,  so  that  no  insulation  is  offered  to  the 
passage  of  static  electricity.  A  lead  from  the  frame  of  the 
machine  could  therefore  take  off  charges  from  all  portions  of  the 
mill.  An  ordinary  box-bearing  is  lubricated  differently,  the  ob- 
ject being  to  establish  a  permanent  him  of  lubricant  between  the 
shaft  and  housing.  This  acts  as  an  insulator  and  an  electrical 
charge  will  not  pass  if  the  lubrication  is  perfect  and  a  complete 
him  established.  So  that  a  mill  with  this  kind  of  bearings 
would  not  be  relieved  of  static  simply  by  a  lead  from  the  frame, 
since  this  lead  would  not  be  taking  the  charge  from  the  shaft  to 
which  the  grinding  plates  are  attached,  and  to  which,  in  the  case 
of  a  belt  drive,  the  pulley  is  attached.  It  would  be  necessary, 
therefore,  to  take  leads  from  contacts  on  both  frame  and  shaft 
to  insure  complete  removal  of  static  charges. 

While  the  conditions  under  which  static  may  be  generated  and 
Stored  up  in  an  attrition  mill  may  be  rather  complex,  arising 
from  kind  of  material  being  ground,  rate  of  feeding,  humidity 
of  atmosphere  and  possible  leakage,  and  the  kind  of  bearings  and 
drive  on  mill,  the  method  for  removal  of  this  type  of  electricity 
is  very  simple  and  effective.  Nothing  more  will  be  said  about 
it  other  than  describing  one  wiring  method  found  to  be  quite  ef- 
fective and  treasured  in  a  large  cereal  mill  in  (  Oakland.  Cali- 
fornia. Two  attrition  mills  in  tin--  plant  had  been  tin-  seat  of 
numerous  fires,  even  though  equipped  with  magnetic  separators. 
This  trouble  went  on  for  months  with  regularity,  and  the  installa- 
tion was  about  to  he  removed,  when  the  mechanical  engineer 
decided  upon   static  electricity  as  the  cause  of  the  fires,     He 

placed  a   brush   on   the  shaft   of   the  mill  and   made  a   contact 
the   frame  of  the   mill,   letting  the   wire   from   this  brush   make  a 
Contact  on  the  frame  of  the  mill.      lie  laid  a  wire  from  this  con- 
tact to  a  c.ntact  on  the  choke  conveyor.      An   insulated   wire   v. 

used  in  wiring  the  machinery,  while  the  ground  wire,  or  the  wire 
leading  to  the  ground  through  a  water  pipe,  was  naked 


wire,  with,  of  course,  no  sharp  angle  turns  in  it.  I  think  there 
were  two  turns  in  the  wire,  both  of  which  were  very  gentle  turns 
that  led  from  the  contact  over  to  a  copper  band  around  the  water 
pipe,  which  was  first  well  scraped  to  insure  good  contact.  That 
is  all  there  was  to  it.  After  he  made  that  installation  the  trouble 
in  the  mill  stopped.  This  may  be  a  coincidence,  but  it  points 
strongly  to  the  danger  of  static  charges  in  mills  of  this  type. 

Some  conclusions  which  I  have  drawn  from  the  series  of  ex- 
plosions in  an  attrition  mill  at  the  cereal  plant  of  the  Sperry 
Flour  Company  at  Stockton,  California,  which  I  have  already 
described  and  which,  of  course,  are  open  to  discussion,  are  as 
follows :  First,  static  electricity  is  generated  in  large  quantities 
at  times  in  an  attrition  mill.  Second,  static  electricity  may  ignite 
ground  oat  hulls  or  oat  hull  dust,  causing  fires  and  resulting  ex- 
plosions, but  to  do  this  the  discharge  must  extend  over  an  ap- 
preciable length  of  time.  Third,  effective  methods  of  wiring 
must  involve  a  study  of  the  possible  paths  of  electricity  and 
insulating  mediums,  and  leads  should  be  taken  from  all  parts 
insulated  from  one  another. 

The  film  of  oil  between  the  shaft  and  housing  of  an  ordinary 
box-bearing  is  an  insulator  preventing  the  passage  of  static  elec- 
tricity, but  such  a  condition  does  not  exist  in  the  case  of  a  ball- 
bearing mill. 

The  purpose  that  I  have  hoped  to  accomplish  at  this  moment 
is  to  draw  attention  to  the  occurrence  and  results  of  static  elec- 
tricity in  the  attrition  process  of  milling.  I  wish  to  emphasize 
my  opinion  that  static  electricity  may  cause  fires  and  resulting 
explosions,  and  that  it  is  a  sensible  precaution  to  remove  static 
charges  from  all  machinery  in  a  plant,  and  especially  from  an 
attrition   mill. 

Dr.  DUVEL — We  have  this  very  interesting  subject  pre- 
sented by  Mr.  McCollam  for  discussion.  T  am  of  the  opinion, 
however,  that  it  will  be  desirable  to  have  Mr.  Roethe's  paper 
first  and  discuss  them  both  at  the  same  time.  They  are  closely 
associated,  and  if  handled  in  this  way  will  save  time,  and  no 
d<  ul >t  avoid  repetition.  There  being  no  objections,  I  will  ask 
Mr.  Roethe  to  presenl  his  paper  on  "Recent  Investigations  of 
Static  Conditions  in  industrial  Plants." 


46 


RECENT  INVESTIGATIONS  OF  STATIC  CONDITIONS 
IN   INDUSTRIAL   PLANTS. 

By  H.  E.  Roethe. 
•  Mr.  ROETHE— Mr.  Chairman:  Upon  the  completion  of  the 
threshing  investigations  in  the  Pacific  Northwest  in  the  summer 
of  1919,  an  opportunity  was  afforded  to  make  a  study  of  static 
electricity  in  representative  mills  and  elevators.  The  electrical 
equipment  used  in  the  case  of  grain  mills  and  elevators  con- 
sisted of  an  Albrecht  type  voltmeter,  a  six-cell  Murdock  con- 
denser, a  spheregap,  and  a  galvanometer  taken  from  an  ordinary 
electrical  resistance  thermometer.  The  investigations  continued 
from  August  22d  to  September  12th,  which  allowed  only  a  lim- 
ited time  at  each  of  the  plants.  The  plants  included  were  the 
Sperry  Flour  Mill  of  Spokane,  the  Fisher  Flour  Mill  of  Seattle, 
the  Sperry  Mill  of  Tacoma,  the  Albers  Milling  Company  plant 
at  Portland,  and  also  the  Portland  Flouring  Mills  and  the  Crown 
Flour  Mills  of  Portland,  the  Washburn-Crosby  "A"  Mill,  the 
Northwestern  Consolidated  "B"  Mill,  the  Northwestern  Con- 
solidated "F"  Mill,  and  the  Northwestern  Consolidated  Elevator, 
all  at  Minneapolis.  Incidentally  the  last  named  elevator  was  the 
only  one  in  operation  in  the  cities  visited,  so  we  could  get  no 
results  of  tests  conducted  at  this  time  in  any  other  elevator.  I 
wish  to  emphasize  the  fact  that  the  results  obtained  were  not 
extensive  enough  to  establish  any  permanent  or  definite  conclu- 
sions regarding  production  of  static  charges  in  grain  mills  and 
elevators.  However,  we  hope  that  the  results  obtained  were  at 
least  of  some  value. 

The  genera]  procedure  was  to  start  on  the  top  floor  of  each 
plant  visited  and  take  the  different  machines  or  series  of  ma- 
chines in  the  order  that  they  were  reached.  Leads  from  the 
voltmeter,  spheregap  and  galvanometer  were  run  to  the  differ- 
ent machines,  and  a  study  was  made  of  static  charges  found  on 
each  part  of  tin-  individual  machines,  and  on  the  machines  as  a 
whole  or  ;i<  a  unit.  The  ground  wire  in  each  case  was  run  to  a 
water  pipe,  or  similar  pipe,  to  Insure  effective  grounding.  An 
effort  was  also  made  to  study  the  relation  of  the  different  parts 
of  the  machine  to  one  another.  For  instance,  it  seemed  advisable 
to  secure  information  regarding  the  difference  •  f  potential  be- 
tween the  roller  on  the  n>ller  mill  and  the   frame  of  the  machine 

itself.     I  give  that  as  an  illustration  to  show  that  we  desired  to 
obtain  results  showing  the  difference  of  potential  between  the 

different  parts  of  the  machine  it-elf  as  well  as  between  the  various 
machinery  and  the  ground. 

47 


Considerable  rain  was  encountered  in  the  Pacific  Northwest, 
in  Seattle  in  particular,  consequently  the  readings  secured  there 
were  not  great,  due  to  the  high  humidity.  Generally  the  ther- 
mometer readings  in  the  Pacific  Northwest  ranged  from  65^2  to 
75  degrees  Fahrenheit,  and  the  relative  humidity  from  22  to  60 
per  cent.  While  in  Minneapolis  the  fore  part  of  September,  we 
found  the  temperature  ranging  from  72  to  82  degrees  Fahren- 
heit, and  the  relative  humidity  ranging  from  34  to  40  per  cent. 
This  shows  that  the  readings  of  humidity  were  higher  and  also 
of  a  greater  range  in  the  Pacific  Northwest  than  at  Minneapolis. 

I  might  just  make  a  few  statements  regarding  positive  and 
negative  electrification,  because  in  giving  the  results  obtained 
reference  is  continually  made  to  these  terms.  The  theory  is  gen- 
erally accepted  that  all  bodies  have  upon  them  a  natural  amount 
of  electricity  which  cannot  be  detected  owing  to  the  fact  that  all 
bodies  have  a  similar  amount.  However,  it  is  possible  to  re- 
distribute this  natural  electricity.  Since  it  is  always  necessary 
for  two  bodies  to  be  electrified  at  the  same  time  and  with  op- 
posite electrifications,  it  is  apparent  that  rubbing  or  friction 
effects  the  redistribution  of  this  electricity  which  existed  upon 
the  bodies  in  its  natural  state.  It  is  also  evident  that  one  body 
acquires  more  than  its  normal  amount  of  electrification,  and  the 
other  body  loses  some  of  its  normal  amount.  There  is,  therefore, 
only  one  kind  of  electricity,  but  two  kinds  of  electrification: 
one  produced  by  an  excess  of  electricity  upon  a  body,  and  the 
other  by  a  deficit.  The  sign  "positive"  or  "plus"  indicates  that 
a  body  has  more  electricity  upon  it  than  is  natural  or  normal, 
and  the  sign,  "minus"  or  "negative,"  that  it  has  less  than  its 
natural  amount.  When  a  positively  charged  body  is  brought 
in  contact  with  a  negatively  charged  or  neutral  body,  a  flow  of 
electricity  takes  place,  electricity  passing  from  the  positively 
charged  body  to  the  other. 

Rather  than  give  the  detailed  results  obtained  at  each  plant 
I  will  summarize  the  readings  made  at  all  the  plants  visited.  We 
found  violent  positive  deflections  on  the  suction  pipes  of  un* 
loading  systems  in  which  grain  was  being  unloaded  from  cars. 
We  aNo  found  100  volts  on  these  pipes.  Workmen  informed 
us  thai  on  hot  dry  days  violent  charges  were  found  on  these 
pipes  when  smutty  wheat  was  being  unloaded.  Tin's  is  in  line 
with  results  obtained  in  similar  tests  on  the  discharge  pipes  of 

tion  fans  on  threshing  machines,  where  very  violent  positive 
deflections  were  recorded  on  the  fan  casing  and  discharge  pipes- 
This  indicate-  very  Strongly  that  the  passage  of  dust,  particularly 

48 


smut  dust,  electrifies  the  metallic  pipe.  In  the  case  of  threshing 
machines  we  have  also  found  positive  electrification  on  the  grain 
pan  over  which  the  threshed  grain  passes,  positive  electrification 
on  all  parts  of  the  elevator,  and  also  on  an  aspirating  system 
which  was  installed  on  one  separator.  In  other  words,  the  pas- 
sage of  grain  and  dust  over  a  dissimilar  material,  such  as  a  metal- 
lic surface,  produced  electrification.  Generally,  we  found  that 
a  metallic  surface  was  positively  charged,  and  the  material  pass- 
ing over  it  was  negatively  charged. 

In  the  case  of  drive  belts,  large  charges  were  always  found 
on  practically  every  belt,  the  charge  depending  upon  climatic 
and  operating  conditions,  the  size,  speed,  material  and  slippage 
of  the  belts  themselves.  A  maximum  of  75,000  volts  was  found 
on  a  leather  drive  belt  in  one  mill  on  the  Pacific  Coast,  running 
from  an  electric  motor  to  the  main  shaft  in  the  basement.  The 
belt  was  22  inches  wide  and  moved  at  a  high  rate  of  speed. 

Conveyor  Belts — Tests  were  made  both  on  troughing  belt  con- 
veyor rolls  and  flat  belt  conveyor  rolls.  Conveyor  belts  do  not 
travel  at  what  we  would  term  great  speed,  generally  moving  at 
the  rate  of  750  feet  per  minute,  or  approximately  SJ/2  miles  per 
hour.  The  slippage  and  friction  is  not  apparently  great  on  such 
belts.  In  a  mill  in  the  Pacific  Northwest  we  found  45,000  volts 
on  a  rubber  conveyor  carrying  smutty  grain  from  the  elevator 
head  to  the  distributors  on  the  top  floor.  A  similar  belt  in  the 
basement  of  the  same  building  gave  a  reading  of  only  200  volts. 
Grain  from  the  same  car  was  being  conveyed  at  the  time  tests 
were  made.  It  is  very  probable  that  the  belt  in  the  basement, 
which  was  conveying  the  grain  from  the  nearby  car,  was  more 
directly  or  effectively  grounded  than  the  belt  on  the  seventh  or 
top  floor,  although  the  entire  building  was  of  concrete  and  steel 
construction.  There  is  a  possibility  that  the  grain,  which  was 
smutty,  was  charged  during  the  process  of  elevation  with  static 
and  transmitted  a  large  part  of  it  to  the  conveyor  belt  above  the 
bins.    No  voltage  was  found  on  canvass  conveyor  belts- 

li levator  boots,  legs,  heads  and  spouts— We   found  no  de- 
flection or  voltage  on  the  boot  in  any  mill  or  elevator  inspected. 
We  found  no  voltage,  but  a  strong  positive  deflection  on  the  K  . 
no  voltage,  but  violent  positive  deflections  on  the  heads;  strong 
negative  deflection  on  the  spouts. 

Separators,  scourers,  etc. — Next,  coming  t<>  the  receiving  and 

milling  separators,  we  Found  no  voltage  or  deflection  in  any  case. 

On  the  scourer^  a  maximum  "t'  1.5(H)  volts  was  Found  on  the 


fan  shaft,  a  maximum  of  2,500  volts  on  the  discharge  pipe,  and 
a  strong  negative  deflection  on  the  fan  shaft  and  discharge  pipe. 

No  voltage  was  found  on  tempering  mixers ;  strong  negative 
deflection  was  recorded  on  the  horizontal  spirals  conveying  wet 
wheat;  none  on  spiral  conveyors  moving  dry  wheat. 

No  voltage  or  deflection  was  found  in  the  magnetic  separa- 
tors with  the  exception  of  the  magnet. 

In  the  roller  mills,  no  voltage  was  found,  but  a  strong  nega- 
tive deflection  was  found  on  the  feed  rollers  and  also  on  the 
rolls. 

No  voltage  or  deflection  was  found  on  the  scalping  and  cen- 
trifugal reels  and  flour  dresser.  The  same  can  be  said  for  sifters, 
including  plansifter  and  bolter. 

No  deflection  or  voltage  was  found  on  middlings  purifiers. 

No  voltage,  but  violent  negative  deflection  was  found  on  bran 
and  shorts  dusters. 

In  the  case  of  the  Williams  grinders,  every  part  was  violently 
charged  with  electricity.  We  found  a  negative  deflection  on  every 
part,  and  1,500  volts  on  the  shafting  and  casing. 

On  the  blower  fans  no  voltage  was  recorded,  although  on 
one  or  two  occasions  we  found  a  violent  negative  deflection  on 
the  intakes  and  discharge  pipes.  On  several  occasions  a  positive 
deflection  was  found  on  the  fan  casing,  fan  shaft,  intake  and 
discharge  pipes. 

No  voltage  was  found  on  the  tubular  dust  collectors,  although 
at  one  time  a  violent  negative  deflection  was  recorded  on  the 
dischaige  pipe. 

On  the  Cyclone  dust-collectors  a  maximum  of  250  volts  was 
found  on  the  drum  and  500  volts  on  the  intake. 

The  surprising  thing  in  regard  to  the  plants  visited  was  that 
no  effort  was  being  made  in  any  of  the  mills  or  elevators  to  carry 
off  the  charges  of  electricity  produced.  We  feel  that  this  should 
be  done  in  the  case  of  the  large  driving  belts,  scouring  machines, 
grinders,  elevator  heads,  blower  fans,  attrition  mills  and  probably 
roller  mills.  In  the  case  of  belts,  the  charge  can  be  very  readily 
disposed  of  by  means  of  belt  dressing  or  a  metallic  comb.  We 
found  that  the  main  drive  belts,  and  those  driving  scourers  and 
grinders,  were  always  heavily  charged  regardless  of  existing  con- 
ditions.  The  scourers  should  be  equipped  with  a  dry  brush  on 
the  shaft,  and  wires  should  be  attached  to  the  discharge  pipe 
and  fan  casing.  It  is  surprising  that  more  fires  do  not  occur  in 
scourer-.  «lnc  to  the  high  speed  of  the  machine  and  to  the  smut 
and  grain  dusts  which  are  always  present.     We  had  no  difficulty 

50 


in  recording  several  thousand  volts  on  every  part  of  the  scourers. 
In  grinding  machines,  it  is  thought  a  dry  brush  should  be  placed 
on  the  shaft,  and  that  wires  be  attached  to  the  casing  and  dis- 
charge pipe.  Here  again  large  charges  were  always  present  oft 
every  part  of  the  machine.  In  the  case  of  elevator  legs  and  heads, 
while  no  voltage  was  recorded,  there  was  always  a  marked  differ- 
ence of  potential  existing  between  the  elevator  head  and  the 
ground.  It  no  doubt  would  be  advisable  to  attach  a  dry  brush 
to  the  pulley  shaft  and  a  wire  to  the  head  itself.  Static  was 
often  found  present  on  the  blower  fan,  on  the  casing,  intake  and 
discharge  pipes.  The  dry  brush  should  be  attached  to  the  shaft, 
and  wires  to  the  casing,  intakes  and  discharge  pipes.  Mr. 
McCollam  has  made  reference  to  the  different  types  of  bearings 
— including  ball  and  plain  bearings  used  on  different  machines 
operating  at  high  speed.  No  doubt  in  case  of  machines  using 
ball  or  roller  bearings,  it  would  not  be  necessary  to  attach  a  dry 
brush  to  the  shaft,  a  wire  connected  to  the  journal  itself  probably 
being  sufficient.  However,  to  insure  effective  removal  of  any 
charges  to  the  ground,  it  might  be  well  to  use  the  dry  brush. 
Wires  can  easily  be  attached  to  the  pneumatic  unloading  systems. 
In  closing,  it  is  not  at  all  easy  to  draw  or  form  any  definite 
conclusions  regarding  the  study  of  static  electricity  in  the  ele- 
vators and  mills  visited,  but  the  results  show  that,  at  certain 
times,  dangerous  conditions  do  exist  on  or  in  scouring  machines, 
grinders,  blower  fans,  and  possibly  the  elevator  head.  Here  con- 
ditions are  most  favorable  for  the  generation  of  static  charges, 
and  an  accumulation  of  them,  and  in  these  machines  and  equip- 
ment dusty  conditions  prevail.  A  hazard  exists  in  the  vicinity  of 
rapidly  moving  large  belts  highly  charged  with  static.  This  danger 
is  all  the  greater  in  the  case  of  arcs  of  static  produced  in  a  dusty 
atmosphere.  A  state  of  electrification  exists  on  metallic  tubing 
through  which  dust  or  grain  is  passing.  The  readings  were 
greater  in  the  case  of  smutty  wheat  or  smut  dust  than  clean  wheat 
or  grain  dust 

Mr.  McCollam  has  already  discussed  static  electricity  in  attri- 
tion mills  most   satisfactorily,  hence  nothing  further  need  be  -aid 

regarding  these  machines. 

Dr.  DUVEL — We  now  have  tor  discussion  Mr.  McCollam's 

paper  on  static  electritcy  in  attrition  mills,  and  Mr.  Koethe\ 
paper  on  static  electricity  in  general,  jn>t  finished.  Some  very 
interesting  points  have  been  brought  out. 


51 


Mr.  PRICE — I  can  recall  that  early  in  this  work  when  a 
dust  explosion  occurred,  and  we  could  not  find  the  cause  readily, 
that  "spontaneous  combustion"  was  usually  assigned.  In  other 
words,  it  meant  that  nobody  knew,  in  the  lack  of  something 
definite,  how  these  explosions  did  occur.  A  few  months  ago 
someone  came  into  our  office,  I  have  forgotten  just  who  it  was, 
and  said  the  insurance  companies  were  no  longer  using  "spon- 
taneous combustion"  but  somebody  had  started  the  theory  that 
always  led  them  to  believe  that  static  electricity  was  the  cause  of 
these  explosions.  After  the  things  we  have  heard  in  both  of 
these  papers,  we  have  been  given  information  which  has  always 
been  looked  for  in  connection  with  this  subject. 

Mr.  McCollam  states  that  in  one  of  the  mills  in  California, 
after  a  series  of  seven  explosions  had  occurred,  in  the  case  of 
an  attrition  mill,  that  the  superintendent  actually  observed  large 
sparks  of  static  electricity  jumping  from  the  grinding  discs  im- 
mediately before  the  explosion.  I  said  yesterday  we  were  trying 
for  a  long  time  to  see  a  threshing  machine  explosion  in  the  north- 
west and  the  difficulties  encountered,  but  here  the  superintendent 
actually  saw  this  explosion.  I  think  that  is  remarkable  evidence. 
Mr.  McCollam  sent  that  report  to  Washington  a  few  months  ago. 

The  results  that  Mr.  Roethe  has  given  us  clear  up  the  difficul- 
ties we  had  in  the  early  days  when  determinations  made  in  ele- 
vators and  mills  indicated  the  presence  of  static  electrical  charges. 
To  my  mind  both  of  these  subjects  have  been  presented  in  a  most 
gratifying  manner,  because  they  have  given  us  facts,  which  have 
cleared  up,  beyond  a  doubt,  the  dangers  existing  in  that  direction. 

MR.  McCOLLAM— In  the  Sperry  Flour  Mill,  where  the  ex- 
plosions occurred,  the  miller  simply  used  the  method  whereby 
contact  was  made  with  the  frame  of  the  machine  and  the  ground 
wire  attached. 

MR.  PRICE — It  appears  that  an  arrangement  where  the  static 
discharge  had  to  pass  through  the  oil  film  might  not  be  as  effective 
as  the  dry  brush  contact. 

MR.  McCOLLAM — There  were  no  explosions  occurring  after 
the  grounding  in  either  case. 

MR.  HODXAR— 1  think  it  would  be  necessary  to  conduct 
sonic  tests  to  determine  this,  in  order  to  prevent  large  maximum 
charges  from  passing  through  a  small  film  of  oil.  It  seems  that 
a  very  small  film  would  let  a  discharge  go  through.  Of  course  I 
do  not  know  how  large  a  charge  it  would  be.  If  oil  insulates  the 
shaft  then  use  a  dry  brush  on  the  shaft. 

52 


DR.  BROWN — In  that  connection  I  might  say  it  has  been 
determined  by  the  Bureau  of  Standards  that  a  film  of  oil  has  ten 
times  the  resistance  to  the  discharge  of  electrical  current  that 
ordinary  air  has.  In  other  words,  the  resistance  of  oil  is  ten 
times  stronger  than  that  of  air.  It  seems  to  me  also 
that  it  is  quite  probable  that  a  dusty  atmosphere  would 
have  a  tendency  to  aid  in  the  passage  of  a  discharge 
through  it  rather  than  to  increase  the  resistance  of  the 
air.  Now,  going  back  to  Mr.  McCollam's  paper.  Mr.  McCol- 
lam  made  the  statement  that  he  felt  that  there  would  not  be 
an  immediate  ignition  of  the  dust  from  a  single  discharge,  but  it 
was  rather  a  question  of  a  series  of  discharges  over  a  short  period 
of  time  through  the  same  dust,  and  it  took  apparently  a  small 
amount  of  time  to  ignite  the  dust  by  means  of  the  static  discharge. 
That  rather  bears  out  one  thing  that  I  brought  out  at  the  last 
conference  last  year  in  connection  with  the  condition  of  cotton. 
We  found  in  making  a  series  of  tests  at  the  Bureau  of  Standards 
that  we  could  ignite  cotton  very  easily  with  a  static  discharge,  but 
that  there  were  two  or  three  controlling  factors ;  that  if  we  main- 
tained a  constant  rate  of  discharge  and  started  with  a  charge  of 
low  intensity,  we  would  have  to  gradually  build  up  the  amperage 
before  we  could  get  any  ignition;  but  then  if  we  decreased  the 
amperage  on  the  static  discharge,  we  could  cut  down  the  fre- 
quency of  the  discharge  and  still  get  an  ignition,  and  so  we  ob- 
tained a  point  at  which  we  could  get  an  ignition  of  cotton  very 
readily  by  simply  one  discharge,  provided  we  had  sufficient  inten- 
sity or  sufficient  amperage  on  the  discharge. 

I  might  refer  to  another  study  of  the  subject  I  am  interested 
in.  As  you  probably  know,  we  had  no  trouble  in  the  northwest 
in  igniting  some  dust  on  the  ordinary  static  machine.  We  have 
not  ignited  any  in  the  laboratory  in  Washington  with  a  static 
spark.  We  have  not  tried  it,  but  I  happen  to  know  that  the 
Bureau  of  Mines  have  done  a  lot  of  work  on  that  line.  Of  course, 
we  feel  that  the  use  of  an  induction  coil  spark  from  an  induction 
coil  is  slightly  different  from  the  static  spark.  On  the  other 
hand,  we  could  control  the  ignition  of  the  cotton  in  the  same 
way  by  speeding  up  the  action  ol  the  induction  coil  as  we  could 

with  the-  Static  machine,  and  SO  1   feel  that  the  discharge  13  lar. 

comparable.    You  may  be  interested  to  know  that  at  the  Bureau 

of  Mines  they  have  had  no  trouble  at  all  in  igniting  SOUK  of  their 

dusts  by  means  of  the  induction  coil  spark  which  is  comparable 
to  the  static  spark.  1  believe  by  blowing,  particularly  gilsonite  dust, 
against  or  over  an  induction  coil  spark.    Gilsonite,  some  of  you 

53 


may  not  know  just  what  it  is,  but  it  is  a  mineral  closely  related 
to  our  asphalt. 

DR.  ALSBERG — I  do  not  know  very  much  about  lubrication, 
but  I  have  been  wondering  whether  you  can  use  graphite  as  a 
lubricant.  Would  not  graphite  act  as  a  good  conductor  for  elec- 
tricity? I  do  not  know  whether  such  a  lubricant  or  modification 
of  it  has  ever  been  used,  but  I  imagine  it  would  act  as  a  pretty 
good  conductor.  Of  course  we  get  good  results  from  the  dry 
brush. 

MR.  BATES — I  have  never  heard  of  graphite  being  used  in 
that  kind  of  a  bearing  in  the  box.  Graphite  is  used  where  heavy 
pressures  occur,  and  where  dust  is  apt  to  collect.  A  dry  lubri- 
cant is  used  sometimes  in  connection  with  oil  to  add  body  to  the 
oil.  The  theory  of  lubrication  is  that  the  adhesion  of  the  lubricant 
to  the  shaft  is  sufficient,  so  that  the  speed  of  the  shaft  will  draw 
the  lubricant  through  under  its  weight  and  thus  bear  the  shaft 
on  a  film  of  oil.  This  condition  exists  only  at  a  speed  and  at 
pressures  varying  with  the  consistency  of  the  oil.  I  believe  that 
would  be  a  very  hard  thing  to  produce  in  graphite.  However,  we 
are  apt  to  think  of  perfect  lubrication  as  providing  a  perfect  film 
of  oil,  and  we  are  apt  to  think  that  we  can  make  the  shaft  in  the 
bearing  perfectly  shaped.  As  a  matter  of  fact,  very  few  bearings 
probably  are  run  at  precisely  the  right  speed  and  with  the  proper 
pressure  to  get  perfect  lubrication,  even  if  you  had  a  perfect 
cylinder  running  on  a  perfect  cylindrical  surface.  Still  it  depends 
upon  the  speed  and  pressure,  while  as  a  matter  of  fact  every 
variation  of  weight  that  occurs  on  your  shaft  is  apt  to  change 
the  angle  of  the  shaft  in  the  bearing,  and  you  are  very  apt  to  find 
the  shaft  itself  imperfect,  so  that  every  revolution  of  the  shaft  is 
not  sufficient  to  draw  in  enough  oil  to  give  good  lubricating 
effects.  That  undoubtedly  accounts  for  the  fact,  as  Mr.  Roethe 
told  us,  that  the  voltage  in  many  cases  docs  not  rise  to  an  amount 
sufficient  to  show  a  deflection  on  some  of  the  shafts  by  voltmeter 
of  the  static  type  ;  that  is,  the  charge  is  similar  on  the  moving  part 
to  that  on  the  stationary  part.  Oftentimes  we  could  not  get  read- 
ings. At  the  same  time  by  using  a  galvanometer  as  a  measuring 
instrument  a  very  small  amount  of  current  affected  the  needle, 
making  it  spring.  We  were  able  to  detect  the  presence  of  cur- 
rent, .although  the  voltage  was  very  small,  undoubtedly  due  to 
the  fact  that  the  voltage  was  not  allowed  to  build  up,  because  at 
a  certain  low  voltage  it  was  neutralized  through  the  bearing. 
That,  by  the  way,  was  the  meaning  of  the  term  that  Mr.  Roethe 

54 


used,  "no  voltage  but  a  strong  deflection. "  You  could  not  have 
"no  voltage  and  a  strong  deflection,"  because  when  taking  the 
readings  there  must  have  been  actual  voltage,  because  no  current 
could  flow  without  voltage. 

I  wish  to  call  your  attention  to  a  misunderstanding  regarding 
this  static  electricity,  as  shown  by  the  fact  that  Mr.  McCollam 
said  we  must  have  as  gradual  curves  as  possible.  The  discharge 
of  electricity  or  the  detecting  of  electricity  through  a  direct  cur- 
rent is  very  well  known,  that  is,  it  follows  very  direct  laws,  and 
we  can  predict  and  conduct  current  of  that  kind  with  a  great  deal 
of  precision.  As  we  get  into  the  alternating  current,  the  laws  are 
varying,  and  up  to  the  frequency  of  the  ordinary  60  cycles  we  can 
predict  what  is  going  to  happen.  When  we  get  to  currents  of 
extremely  high  frequency,  such  as  you  have  discharged  on  alter- 
nating current,  electricity  violates  all  the  laws.  An  alternating 
current  would  readily  jump  an  air-gap  in  preference  to  following 
a  coil  wire,  and  for  that  reason  you  find  electric  light  plants 
putting  conductors  of  heavy  copper  wire  on  the  outside  of  their 
buildings.  We  are  taking  the  static  as  it  is  generated,  and  we 
do  not  have  that  frequency  because  there  is  no  discharge  through 
the  air.  When  a  spark  jumps  through  the  air  it  burns  a  hole 
through  the  air  and  becomes  a  good  conductor,  until  it  finally  dies 
out,  and  we  do  not  get  that  current  as  it  is  generated  on  these 
machines.  Therefore,  the  best  practice  would  be  to  put  your 
wires  where  they  are  best  protected,  running  them  through  any 
holes,  in  corners  or  any  place,  but  have  them  well  protected, 
and  the  angles  will  have  no  effect  on  the  current.  This  is  some- 
thing we  should  understand,  because  if  we  attempt  to  make  them 
place  their  wires  in  long  smooth  curves,  we  might  get  away  with 
it  all  right  so  far  as  the  millers  are  concerned,  but  some  of  the 
electrical  engineers  might  view  it  with  some  reflection  on  our 
knowledge  of  electrical  principles. 

Mr.  McCOLLAM — I  might  say  in  reply  to  that,  with  ref- 
erence to  the-  installation  in  the  Oakland  plant,  that  before  making 
that  wiring  installation  they  asked  the  General  Electric  Company 
for  any  information  they  might  have  on  the  subject  for  wiring  on 
static  electricity,  and  the  diagram  they  gave  was  Followed  out, 
and  that  was  one  of  the  special  features  in  that  plant — naked 
copper  win-  and  the  precaution  against  angle  turn-. 

Mr.  BATES  1  certainly  will  have  to  admit  that  the  authority 
Is  good,  but  1  do  not  in  the  least  alter  my  statement 


55 


Dr.  ALSBERG — I  wonder  whether  I  am  correct  in  my  under- 
standing that  you  do  not  get  any  charges  on  canvas  belts. 

Mr.  ROETHE — The  only  canvas  belts  available  for  tests  were 
on  conveyors.  No  voltage  was  found  on  these  belts  and  no  deflec- 
tion, as  indicated  by  the  galvanometer. 

Dr.  BROWN — It  has  been  suggested  that  graphite  is  used  to 
a  certain  extent,  and  Mr.  Price  has  some  information  on  that. 

Mr.  PRICE — The  information  we  have  is  more  or  less  hear- 
say. I  understand  that  a  company  in  New  York  has  made  con- 
siderable progress  along  that  line ;  just  what  it  is  I  am  not  in 
position  to  say. 

Mr.  HIBBARD — It  is  just  plain  belt  dressing  to  prevent 
slipping.    Just  what  the  composition  is  I  do  not  know. 

Dr.  BROWN — What  was  the  determination?  Was  the  sign 
of  the  charge  on  the  different  belts  negative  or  positive? 

Mr.  ROETHE — Generally  we  found  positive  sign  on  belts 
and  negative  on  the  metallic  pulleys  and  idlers,  although  in  some 
cases  just  the  reverse  was  true.  We  secured  no  readings  on  the 
discharge  pipes,  although  we  did  find  that  the  pipes  were  ap- 
parently electrified  to  a  certain  extent  because  the  chaff  would 
adhere  to  the  pipe  in  a  vertical  position.  The  chaff  was  blown 
out  by  suction  fans  on  threshing  machines. 

Mr.  PRICE — This  stands  out  prominently  in  connection  with 
what  we  have  been  trying  to  find  out  and  have  been  doing.  I 
want  to  ask  Mr.  McCollam  now  regarding  this  superintendent 
who  observed  this  explosion.  On  what  basis  did  he  decide 
whether  those  sparks  were  not  caused  by  the  plates  rubbing  or 
by  metallic  substances  passing  through  the  machine?  What  sat- 
isfied the  superintendent  in  his  mind  that  they  were  electrical 
sparks,  and  not  metallic  sparks? 

Mr.  McCOLLAM — The  miller  made  no  electrical  determina- 
tions on  the  machine  other  than  with  the  gold-leaf  electroscope, 
and  with  tins  instrument  he  found  very  violent  charges  every 
time  he  touched  the  frame  of  the  machine.  He  went  throughout 
the  plant  and  found  other  machines  that  had  static  electricity  on 
them.     This  was  the  only  method  that   he  employed  to  base  his 

Limption  that  the  explosions  were  being  caused  by  static  elec- 
tricity, lie  had  made  a  study  of  static  electricity  and  knew  just 
what  kind  of  a  Spark  it  made  at  the  time  of  the  most  violent  explo- 
sion.   1  lc  was  able  to  observe,  in  the  housing  of  the  mill,  the  color 

56 


of  these  sparks,  and  he  called  my  attention  to  that  very  forcibly 
and  said  that  proved  in  his  mind  it  was  caused  by  static  electricity, 
and  as  I  say,  he  mentioned  the  fact  that  the  sparks  were  of  light 
blue  color,  which  is  characteristic  of  the  static  spark,  and  I  do 
not  believe  grinding  plates  rubbing  together  would  produce  sparks 
of  that  color  at  all. 

Mr.  BATES — I  believe  sparks  which  would  be  caused  by 
abrasion  or  by  something  hard  striking  the  rotating  plates,  would 
fly  of!  at  a  tangent,  while  the  electric  spark  would  not  be  affected 
by  the  motion  of  the  plate  but  would  jump  across  the  air-gap 
between  the  plates.  Another  way  to  identify  the  sparks  is  by  the 
color.  I  have  had  thresher  men  state  that  on  occasions  when 
they  threshed  grain  after  dark,  the  cylinder  of  the  machine  was 
a  perfect  glow  of  blue  fire.  This  indicates  that  there  is  often 
a  continual  discharge  of  static  electricity  at  thresher  cylinders, 
but  that  it  is  only  the  hundred  millionth  spark  that  occurs  in 
just  exactly  the  right  condition  to  start  a  fire.  Electrical  dis- 
charges in  threshing  machines  are  dangerous  only  when  the  other 
conditions  are  favorable  to  make  the  explosion. 

Dr.  DUVEL — Is  there  any  further  discussion  on  this  subject? 

Mr.  FOX,  of  the  Edison  Lamp  Works — One  point  might 
be  of  interest  regarding  electric  lighting.  When  going  through 
a  mill  the  ordinary  electric  light  bulbs  can  be  used  to  detect  the 
presence  of  static  electricity.  The  filaments  in  bulbs  when 
burned  near  machinery  charged  with  static  electricity  will  be 
bowed  out,  and  in  some  instances,  especially  in  the  ordinary  car- 
bon lamp,  the  filaments  may  be  drawn  to  the  edge  of  the  bulb 
and  cause  it  to  crack  or  break.  We  found  considerable  diffi- 
culty along  this  line  with  certain  types  of  lamps. 

Mr.  BATES — Would  it  be  safe  to  use  electric  light  bulbs 
next  to  a  machine  to  detect  a  static  charge? 

Mr.  FOX — I  do  not  know  just  how  sensitive  this  would  be 
or  Imw  small  a  static  discharge  could  be  detected. 

Mr.   BATES  -1   have  seen  that  tried  on  carbon  filaments. 

You  can  take  a  carbon  lamp  and  rnl>  a  rubber  comb  through  your 
hair  and  draw  the  filaments  almost  to  the  side  of  the  bulb  when 

u  is  burning. 

Mr.    FOX — That    was   the   trouble   in   carbon   lamps,   the   li!a 

ments  being  drawn  to  the  side  of  the  bulb  and  eventually  crack- 
ing the  bulb. 


Dr.  DUVEL — There  is  one  point  which  Mr.  Roethe  men- 
tioned in  his  paper  relative  to  tests  for  static  on  belts  when 
handling  different  kinds  of  grain.  I  would  like  to  ask  if  any 
of  the  men  have  made  any  tests  of  thir  character  in  the  handling 
of  flax.  I  think  it  is  generally  conceded  that  flax,  after  it  has 
been  handled,  becomes  electrified ;  at  least,  flax  handlers  find 
after  handling  flax  through  an  elevator  that  the  test  weight  per 
bushel  is  decreased  sufficiently,  frequently  to  cause  the  loss  of  a 
grade.  There  are  probably  two  causes  which  play  an  impor- 
tant part :  First,  the  roughening  of  the  seed  coat,  which  is 
normally  very  smooth,  and  permits  the  seed  to  pack  well  in  the 
test  kettle ;  Secondly,  the  question  of  electrification.  In  some 
experiments  conducted  at  the  Department  of  Agriculture,  we 
took  a  test  kettle  filled  with  flaxseed  and  stroked,  showing  a  test 
weight  of  52  pounds.  This  seed  was  then  placed  in  an  ordinary 
.Mason  fruit  jar  and  shaken  slowly  back  and  forth  500  times, 
then  reweighed.  On  the  reweighing  the  flaxseed  more  than  filled 
the  test  kettle  and  there  had  been  a  loss  in  the  test  weight.  This 
was  repeated  for  an  additional  500  shakes,  still  an  additional 
500,  and  still  an  additional  500,  making  in  all  2000,  weighings 
being  made  after  each  500  shakes.  In  each  instance  there  was 
an  additional  quantity  of  seed  which  would  not  go  into  the  test 
kettle  and  also  an  additional  decrease  in  the  test  weight.  As  I 
recollect,  the  final  weight  was  48  or  49  pounds,  being  a  loss  of 
3  or  4  pounds.  Whether  or  not  this  was  due  to  electrification 
or  merely  to  a  roughening  of  the  seed  coat,  I  am  not  able  to 
say  positively,  but  it  is  probable  that  both  factors  had  some 
influence. 

Dr.  DUVEL — Any  further  discussion? 

Mr.  REED — Several  weeks  ago  I  had  an  interesting  experi- 
ence with  static  electricity  that  may  be  of  interest  to  those  pres- 
ent. While  at  Winchester,  Va.,  I  met  the  president  of  the  Vir- 
ginia Woolen  Mills  and  during  my  talk  with  this  gentleman,  I 
was  informed  that  they  experienced  considerable  difficulty  in 
the  carding  of  their  wool.  He  stated  that  on  certain  dry  or 
windy  days,  in  a  certain  portion  of  the  plant  which  was 
exposed  to  the  wind,  their  carding  machines  would  not  operate 
properly,  due  to  the  fact  that  the  static  electricity  which  had 
accumulated  on  the  carding  machine  would  turn  the  wool  and 
make  ;t  stand  on  end.  The  wool,  in  being  carded,  runs  over  a 
large  cylinder  and  is  taken  up  at  certain  points  by  another  cylin- 
der which  has  teeth  on  it,  and  in  that  way  every  strand  is 
Straightened  out.     Finally  this  wool  is  combed  off  the  side  of 

58 


the  large  cylinder  and  is  run  through  two  large  rubber  belts 
which  slide  back  and  forth  and  rub  the  wool  together.  The 
most  difficulty  they  had  with  static  was  in  running  the  wool  be- 
tween those  two  belts.  There  was  an  equal  amount  of  friction 
between  those  two  belts  and  the  static,  which  would  in  some 
manner  straighten  out  this  wool  and  make  it  stand  out  on  the 
side.  As  a  result  they  would  not  get  a  perfect  cord,  or  what- 
ever it  was  they  were  trying  to  form  (I  am  not  familiar  with  the 
terms  they  use).  I  went  into  the  plant  and  looked  over  the 
machinery.  They  were  trying  to  keep  the  humidity  in  the  plant 
as  high  as  possible.  In  one  section  of  the  plant  where  they  had 
carding  machines  installed  above  the  dye  room,  from  which 
there  was  a  large  quantity  of  steam  coming  up,  they  had  experi- 
enced no  such  difficulty.  That  section  of  the  plant  is  high  and 
not  exposed  to  the  wind,  but  on  the  west  exposure  they  experi- 
enced considerable  difficulty.  I  recommended  that  a  comb  be 
placed  on  this  belt  and  at  the  same  time  some  sort  of  a  comb  be 
placed  upon  the  rotating  cylinders.  There  is  considerable  diffi- 
culty in  the  grounding  of  these  cylinders  due  to  the  fact  that 
the  combs  on  the  cylinder  are  imbedded  in  a  cotton  or  woolen 
fabric.  The  combs  on  the  cylinder  do  not  touch  the  cylinder 
itself,  which  is  made  of  steel,  but  each  comb  is  separate,  and  is 
imbedded  into  this  woolen  fabric.  Once  a  month  they  are  com- 
pelled to  grind  these  combs.  One  man  told  me  that  on  one 
occasion  he  grounded  a  carding  machine  to  a  spool  frame  and 
said  they  had  very  good  results. 

Dr.  DUVEL — That  is  a  very  interesting  observation. 

Dr.  BROWN — In  our  work  in  cotton  we  made  an  experiment 
whereby  we  pulled  the  cotton  through  a  suction  pipe  and  allowed 
it  to  strike  against  an  insulated  screen.  We  found  a  charge  on 
the  pipe  and  one  on  the  screen  and  these  were  almost  equal. 
When  we  gathered  these  together  we  had  no  charge.  On  actual 
determination  we  found  an  i  mount  <>n  the  pipe  over  that 

on  the  screen,  and  we  found  that  the  equal  amount  of  the  posi- 
tive si'ltii  on  the  charge  was  ^till  on  the  cotton.     In  reality  we 
might    have   had   two   different    types    of   charges    which    - 
neutralized. 

Dr.  DUN  EL     It"  there  is  no  further  discussion  of  the  two 
papers  dealing  with  static  electricity,  we  will  take  tin-  report  of 
Mr.  Price  on  ••Relation  of  Electrical  Equipment  to  Dust 
sioi 


"RELATION  OF  ELECTRICAL  EQUIPMENT  TO  DUST 

EXPLOSIONS." 

By  D.  J.  Price. 

Air.  Geo.  H.  Rice,  who  was  to  present  this  paper,  as  you  know, 
went  with  the  Hartford  Fire  Insurance  Company  the  first  of 
the  month.  I  am  not  going  to  attempt  to  discuss  the  entire 
matter  of  electrical  equipment  in  so  far  as  it  applies  to  mills  and 
elevators,  but  want  to  present  to  you  in  a  brief  way  what  we 
have  been  doing  with  the  electric  lamp  companies  in  connection 
with  that  phase  of  our  electrical  problem.  You  are  somewhat 
familiar  with  the  nature  of  that  co-operation  and  have  been  in- 
formed from  time  to  time  of  what  has  been  done. 

At  the  time  of  the  Kansas  City  explosion  last  September  our 
investigation  was  very  difficult  to  conduct  and  definite  evidence 
was  lacking  in  many  ways.  One  of  the  survivors,  in  fact  the 
only  one,  said  that  he  remembered  noticing  a  blue  flash,  near  the 
ceiling  just  before  the  explosion.  It  developed  that  the  part  of 
the  basement  where  he  had  seen  the  flash  was  about  the  location 
of  one  of  the  electric  lamps.  This  suggested  the  possibility  that 
the  lamp  may  have  ignited  the  dust.  We  made  renewed  efforts 
to  ascertain  if  this  was  the  cause  of  the  explosion.  At  the  time 
the  first  poster  was  issued  by  the  Department  of  Agriculture  and 
the  Food  Administration,  in  view  of  the  large  number  of  cases 
brought  to  our  attention  where  workmen  had  been  lowering 
electric  bulbs  into  dusty  bins  and  explosions  had  occurred,  we 
felt  that  a  warning  of  some  kind  should  be  given  to  the  men. 
We  made  five  or  six  simple  recommendations  along  precautionary 
lines  and,  as  you  recall,  one  of  those  measures  suggested  that 
the  men  refrain  from  lowering  unprotected  electric  lamp  bulbs 
into  dusty  atmospheres,  or  bins.  That  caused  interest  on  the 
part  of  the  lamp  companies.  Considerable  correspondence  was 
received  in  Washington  from  the  Westinghouse  Company. 

They  wanted  to  know  what  reason  we  had  for  making  a 
recommendation  of  that  kind.  They  referred  to  the  work  that 
had  been  done  at  Pennsylvania  State  College  in  connection  with 
our  attrition  mill  experiments  and  raised  the  question  as  to 
whether  or  not  we  actually  had  conducted  experimental  work 
showing  that  the  use  of  these  electric  lamps  was  dangerous. 
We  had  not  done  s()<  hut  felt  that  in  view  of  the  cases  in  the 
field  some  warning  should  he  -oven. 

The  Kansas  City  explosion  led  to  direct  relations  being  opened 

up  between  the  Grain  Corporation  and  the  different  lamp  com- 
panies.   We  have  had  a  number  of  very  satisfactory  conferences. 

60 


The  three  companies  concerned  are  the  National  Lamp  Works 
of  Cleveland,  the  Westinghouse  Company  at  Bloomfield,  N.  J., 
and  the  Edison  Company  at  Harrison,  N.  J.  In  these  conferences 
we  have  tried  to  work  out  definite  lines  of  experimental  work 
and  further  investigations- 

The  work  handled  divides  itself  into  two  simple  classes :  first, 
the  possibility  of  explosions  being  produced  by  the  breaking  of 
the  bulbs  in  dust,  and,  second,  the  possibility  of  fire  or  explo- 
sion from  dust  settling  on  the  lamp.  The  first  suggestion  was 
almost  cleared  up  immediately,  as  you  know,  in  the  work  at  Cleve- 
land. In  the  tests  conducted  there,  within  a  short  time  after 
the  engineers  began  the  work,  they  established  very  definitely 
that  any  type  of  lamp  broken  in  a  dust  cloud  will  cause  an  ex- 
plosion. We  covered  that  phase  of  the  work  largely  in  our  meet- 
ing in  Cleveland  in  January.  We  have  a  number  of  cases  in  the 
field  reported  where  explosions  have  been  assigned  to  that  par- 
ticular cause.  The  experimental  work  settles  beyond  any  doubt 
that  the  breaking  of  the  lamp  in  the  dusty  atmosphere  will  cause 
an  explosion.  However,  at  the  time  of  issuing  the  poster  we 
thought  that  for  some  reason  carbon  lamps  were  more  dangerous 
than  the  tungsten  type,  and  even  went  so  far  as  to  suggest  re- 
placing all  carbon  lamps  with  tungstens,  in  some  of  the  elevators, 
hoping  that  we  were  getting  away  from  the  danger.  We  found 
in  the  experimental  work  that  the  breaking  of  the  tungsten  was 
just  as  dangerous  as  the  carbon  type. 

The  second  phase  of  the  experimental  work  is  giving  us  more 
concern.  At  a  conference  held  in  New  York  a  few  weeks  ago  it 
developed  that  difficulty  had  been  experienced  in  determining 
whether  or  not  ignition  actually  occurred  by  dust  settling  on 
the  lamps.  I  understand  from  Mr.  Dows  and  Mr.  Hills  that  in 
the  work  at  Cleveland  the  dust  would  smolder  or  -moke  but  they 
were  not  able  to  conduct  any  tests  where  the  dust  reached  a  point 
of  incandescence  or  glowing  heat.  In  the  last  conference  the 
representatives  of  the  lamp  companies,  after  being  furnished  with 
a  number  of  specific  cases,  as  you  recall — the  cases  sent  in  from 
the  field — made  a  number  of  inquiries  that  had  been  suggested 
by  tin-  cases  submitted,  that  related  to  fires  being  I  in  that 

manner.     To  get  the  information  in  an  authentic  v.  took 

iij >  with  yon.  by  correspondence,  tin-  cases  that  you  had  reported. 
We  sent  tin-  lamp  companies,  at  their  request,  I  think  17  or  18 
cases  of  fires  caused  in  that  manner.  Now",  what  we  are  trying 
to  find  out  is  whether  in  these  cases  that  have  been  reported  the 
men  actually  saw  a  -lew  or  the  dust  reached  incandescence  or 

61 


whether  it  was  just  smoking.  The  engineers  of  the  lamp  com- 
panies are  not  doubting  these  facti  but  desire  to  determine 
whether  the  dust  was  actually  seen  to  be  on  fire.  Now,  to  cite  a 
case  of  what  I  have  in  mind,  Mr.  Court  of  New  Orleans,  as  you 
will  recall,  at  the  Chicago  conference,  related  the  following  ex- 
perience (No.  4)  : 

A  workman,  in  a  southern  elevator,  related  an  experience  he 
had  while  using  an  electric  light  in  a  dusty  atmosphere.  He  had 
been  sent  down  into  a  small  and  narrow  bin  to  do  some  cleaning. 
As  he  climbed  down  and  brushed  off  the  ladder  which  led  down 
into  the  bin,  he  lowered  the  light  into  the  opening  ahead  of  him. 
During  the  cleaning-up  process  a  great  amount  of  the  dust  fell 
on  the  lamp  and  in  a  short  time  dimmed  the  light.  The  workman 
immediately  climbed  down  to  the  suspended  light  and  noticed 
that  the  dust  on  the  globe  was  on  fire.  He  did  not  know  whether 
he  should  pick  up  this  fire,  put  it  into  his  pocket  and  run  up  the 
ladder,  or  try  to  extinguish  the  flames  down  in  the  pit.  He 
climbed  out  of  the  bin  and  turned  off  the  current  to  the  light. 
As  he  states,  every  minute  he  expected  to  be  blown  to  pieces,  but 
he  escaped  because  there  was  not  enough  dust  in  suspension  to 
propagate  the  flames.  From  that  time  on  vapor-proof  bulbs  ivere 
placed  on  the  extension  lights  in  that  elevator. 

Now,  we  recall  very  definitely,  Mr.  Court  gave  that  experi- 
ence almost  word  for  word  and  so  we  took  the  matter  up  with 
him  by  correspondence  and  have  a  letter  from  him  here.  This 
was  done  after  our  last  conference  with  the  lamp  companies. 
Mr.  Court  states: 

"Received  your  letter  this  afternoon  and  in  reply  to 
my  experience  in  elevator  leg,  when  I  was  brushing  down 
the  ladders  I  had  put  the  portable  light  half-way  down  the 
leg,  and  as  I  was  going  down,  I  was  cleaning  the  steps 
and  never  noticed  anything  until  1  got  to  the  light.  As 
the  globe  was  very  dusty  and  1  noticed  it  was  smoking 
and  very  hot  and,  I  believe,  I  saw  small  sparks,  as  I  was 
in  a  hurry  to  get  back  up  stairs.  We  had  another  ex- 
perience at  same  elevator.  The  men  were  cleaning  out 
the  pit  and  were  using  a  portable  light  without  protector, 
and  at  noon  time  the  men  went  to  dinner  and  didn't  put 
the  light  out,  and  when  we  got  hack  from  lunch  we  noticed 
a  lot  of  Smoke  Coming  from  the  pit  and  we  got  a  hose  and 

put  water  on  it.     I  believe  it  was  only  smoldering  at  the 

time  as    I    didn't    see  a   flame,   hut    think   there   would  have 

been  a  flame  if  it  would  have  had  a  draught.91 

62 


There  were  three  distinct  cases  reported  from  Minneapolis. 
Case  No.  5.  "The  superintendent  of  a  large  Northwestern  ele- 
vator relates  that  during  the  period  that  he  has  been  engaged  as 
superintendent  of  an  elevator  he  can  recall  from  twenty-five  to 
thirty  fires  which  originated  from  carbon  lights.  The  dust  coating 
on  the  globes  became  aflame  and  dropped  to  the  floor,  a  small 
fire  resulting." 

We  wanted  to  get  the  name  of  the  elevator  and  the  superin- 
tendent so  that  the  information  for  the  lamp  companies  could 
be  accurate  and  complete.  This  case  was  reported  by  Mr.  Lind 
of  Minneapolis  and  was  taken  up  with  him  with  this  result : 

"During  your  recent  visit  here  attending  conference 
held  in  this  office  you  will  perhaps  recall  a  discussion  we 
had  regarding  experiences  Mr.  D.  K.  Whalen  has  had  with 
carbon  lights.  Mr.  D.  K.  Whalen  is  manager  of  the  Ex- 
change Elevator,  St.  Louis  Park,  a  surburb  of  Minneapolis. 
It  will  be  remembered  that  at  a  previous  visit  I  had  with 
Mr.  Whalen  the  question  of  various  electric  lighting  equip- 
ment was  discussed  with  him,  and  at  that  time  he  related 
some  experiences  he  has  had  with  carbon  lights.  After 
relating  these  experiences,  you  advised  that  I  again  get  in 
touch  with  Mr.  Whalen,  and  particularly  some  of  the  men 
who  have  had  like  experiences,  for  the  purpose  of  verifying 
or  substantiating  through  these  men  the  facts  of  the  case. 

Mr.  Whalen  advised  that  during  his  connection  with 
the  Exchange  Elevator  no  less  than  twenty -five  or  thirty 
smoldering  carbon  globes  have  been  observed  in  this  plant. 
By  this  is  meant  that  the  dust  would  gather  on  the  globe 
in  layers,  and  because  of  the  intense  heat  coming  from 
a  carbon  light,  said  dust  would  begin  to  smolder,  and  very 
often  this  smoldering  dust  was  seen  to  drop  to  the  floor 
where  it  came  in  contact  with  dusl  there,  but  nothing  of 
anv  serious  nature  happened  to  develop. 

V  a  recent  conference  with  Mr.  Whalen  and  some  of 
the  help,  it  was  brought  out  very  clearly  by  these  men 
that  the)  had  the  -aim-  experiences  in  the  past.  This  is 
merely  to  advise  you,  as  you  requested,  of  the  correctness 
of  Mr  Whalen's  experience 

1  understand  that  Mr.  Brady  -aw  this  superintendent  further 

an.l  that  he  also  has  information,  if  1  am  correct,  that  the  work- 
men made  the  statement  that  the)  actually  shoveled  the  fire  out, 
so  that  the  tire  actually  took  place  when  this  smoldering  dust 


reached  the  dust  on  the  floor.     Mr.  Brady  after  talking  with  Mr. 

Whalen  stated : 

''Case  No.  5  was  witnessed  by  Mr.  D.  K.  Whalen  of 
the  Exchange  Elevator,  Minneapolis.  In  a  talk  with  Mr. 
Whalen  on  the  telephone  to  confirm  his  experience  will 
say  that  he  claims  to  have  actually  seen  the  dust  ignited 
and  glowing.  The  dust  coating  on  the  globes  became 
aflame,  dropped  to  the  floor  and  ignited  dust  down  there. 
He  claims  there  is  no  question  about  this,  and  that  actual 
flame  was  seen." 

When  I  was  in  Minneapolis  we  got  in  touch  with  Mr.  Whalen 
and  cleared  up  to  my  satisfaction  that  the  dust  was  actually  seen 
glowing  by  the  superintendent  and  workmen. 

The  two  other  cases  reported  were  witnessed  by  Mr.  O.  E. 
Lee,  superintendent  of  the  Interstate  Elevator  and  Mr.  R.  W. 
Cote  of  the  Cargill  Elevator  Company,  where  these  fires  were 
thought  to  have  occurred,  but  as  1  remember  they  were  not  sure 
that  they  saw  the  flame. 

Since  we  had  our  conference  at  Cleveland,  Mr.  Rice,  who  was 
to  handle  this  matter,  had  an  experience  in  St.  Louis,  in  which 
he  stated  to  me  he  understood  that  the  dust  was  seen  to  be 
glowing — had  reached  the  point  of  incandescence.  The  statement 
"glowing  very  brightly''  was  token  up  by  Mr.  Rice  directly  with 
this  company  in  St.  Louis.  That  was  a  recent  case  in  St.  Louis, 
and  there  were  a  number  of  others,  some  on  the  Pacific  Coast  re- 
ported by  Mr.  Bodnar  and  some  others  in  different  parts  of  the 
country.  I  have  referred  to  only  a  few  eases  in  the  17  or  18 
cases  reported,  hi  a  number  of  them  it  seems  almost  certain  that 
the  dust  was  actually  seen  to  glow  or  reach  the  incandescent 
point,  while  Other  cases  were  reported  where  the  dust  was  only 
smoking  or  smoldering. 

If  the  reports  had  been  all  alike,  the  work  at  Cleveland  might 
-ccni  to  indicate  difficulty  in  producing  an  explosion  or  fire  from 
this  cause.  In  the  tests  we  have  not  been  using  light  fluffy 
elevator  dust,  but  mostl)   starch  dust.     Whether  it  was  not  the 

right    kind   of    dust    or   conditions    were   not    similar   to   operating 

conditions  will  have  to  be  determined  later  by  further  experiment. 

It  is  a  question  that  seems  to  be  an  important  phase  of  the 
electrical  work,  because  we  have  felt  that  possibly  if  the  tire  would 
drop  through  the  proper  proportion  of  dust  and  air  an  explosion 

would  occur,  but  we  have  no  information  to  indicate  that  such  is 

the    case.       hire    probabU     would    occur    when    that    (lust    on    lire 

hes  the  floor.     Von  will  be  interested,  probably,  in  knowing 

64 


that  in  connection  with  the  program  sent  to  the  lamp  companies 
at  their  request  sometime  ago  we  outlined  lines  to  be  followed 
in  experimental  work.  Twenty-four  distinct  lines  were  sug- 
gested by  the  men  on  the  work.  At  the  conference  with  the 
engineers  of  the  lamp  companies  in  New  York  recently  it  was 
decided  that  these  lines  of  work  should  be  divided,  some  to  be 
taken  up  at  Cleveland,  O.,  sgme  at  Harrison,  X.  J.,  some  at 
Bloomfield,  N.  ].,  and  some  in  the  electrical  laboratories  at 
Pennsylvania  State  College.  On  some  of  the  lines  that  have  been 
suggested,  of  course,  the  lamp  companies  have  the  information 
available,  but  there  is  still  quite  a  little  work  to  be  done  ex- 
perimentally on  the  problem  and  we  are  hoping  that  even  in  view 
of  the  uncertainty  as  to  what  we  can  do  after  July  1,  we  can 
take  care  of  this  phase  of  the  work.  The  lamp  companies  have 
been  co-operating  with  us  so  splendidly  that  we  hope  to  be  able 
to  make  some  provision  for  a  continuation  of  the  work. 

When  I  was  in  Denver  some  time  ago  the  manager  of  one  of 
the  large  grain  interests  in  the  Northwest  (  1  think  he  told  me 
he  had  175  plants)  took  up  this  question  with  me.  He  told  me 
that  they  had  ordered  one  Marine  type  fixture  for  every  plant 
so  that  the  superintendent  could  try  it  out  and  see  how  he  liked 
it.  I  thought  that  was  a  very  marked  achievement,  because  the 
company  took  it  up  with  us  at  Washington  and  merely  on  our 
suggestion  immediately  got  in  touch  with  electrical  companies 
and  secured  this  equipment.  The  trade  is  demanding  and  re- 
questing information  on  this  line.  As  we  discussed  at  Cleveland, 
we  say  we  cannot  Use  lanterns,  we  cannot  use  open  lights,  we 
condemn  gas  jets,  we  are  finding  fault  with  electric  light-,  and 
we  are  unable  to  recommend  a  light  that  is  safe.  I  am  very 
happy  to  state  that  the  engineers  of  the  lam])  companies  feel  now 
that  it  will  he  possible  to  overcome  this  difficulty.  It  may 
require  a  vapor-proof  globe  in  all  cases.  In  lack  of  further 
information  we  an'  recommending  that  vapor-proof  globes  should 
he  used  in  all  case  us  away    from  these  dangers  that 

present  themseh  • 

1  have  confined  myself  entirel)  to  this  work  with  the  electric 
lamp  companies  because  Mr.  Fox  From  the  Edison  Lamp  Work- 
is  here  with  us.  Someone  may  have  something  additional  to 
offer  regarding  cases  which  have  hern  observed  b)  you  "i  brought 
to  your  attention  where  <lust  has  reached  the  incandescent 
and   lire   resull 


65 


Dr.  DUVEL — We  have  this  very  interesting  paper  before 
us  and  as  Mr.  Price  has  said,  in  this  work  we  have  enjoyed  the 
assistance  and  co-operation  of  the  three  big  electric  companies,  the 
Edison,  YYestinghouse,  and  National  lamp  companies,  and  I  want 
to  say  in  this  connection  that  I  think  that  has  been  very  helpful 
co-operation  in  every  way.  We  have  the  pleasure  of  having 
with  us  this  morning  Mr.  Fox  of  the  Edison  Company  and  1 
would  like  to  have  him  open  this  discussion  and  present  some 
of  his  own  results  and  reports,  in  fact,  I  might  suggest  that  he 
present  these  results,  first,  and  the  discussion  can  follow. 

SPECIAL  FEATURES  IN  LIGHTING. 

By  E.  B.  Fox,  Commercial  Engineer,  Edison  Lamp  Co. 

Mr.  FOX — (First  makes  sketch  on  blackboard,  Fig.  1.)  We 
have   had    several    letters    requesting   information   about   a    mill 


Fig.    1. 
Mill    type    lamp. 


type  lamp  and  there  seems  to  be  possibly  a  little  misunderstand- 
to  in  i  what  thai  lamp  is.  The  mill  type  lamp  some  people 
think  burns  at  a  low  temperature,  but  there  is  really  very  little 
difference  in  temperature  between  the  mill  type  and  the  regular 
vacuum  lamp.  Tin's  mill  type  lamp  was  invented  for  places 
where  you  have  a  great  deal  of  vibration.  In  an  ordinary  lamp 
when  the  filaments  are  burning  they  get  soft  and  are  apt  to  come 


together,  stick  and  lock,  which  cuts  out  part  of  the  filament  and 
the  rest  of  it  is  burned  at  a  much  higher  temperature,  which  cuts 
down  the  life.  In  the  mill  type,  part  of  the  filament  is  held  by 
short  anchors  (Fig.  1-A)  and  that  brings  this  part  of  the  filament 
(indicating)  out  of  the  plane  of  the  adjoining  part  and  makes  it 
impossible  for  the  two  to  lock  together,  no  matter  how  much  vibra- 
tion there  may  be.  There  is  also  a  little  steel  connection  in  the 
form  of  a  spring  (Fig.  1-B),  so  that  the  stem  is  able  to  vibrate. 
This  last  simply  makes  the  lamp  stronger.  The  difference  in 
temperature  between  the  two  lamps  is  not  over  five  or  ten  de- 
grees Centigrade. 

The  thing  that  got  the  lamp  companies  started  on  this  dust 
explosion  work  was  that  the  Millers'  Mutual  made  a  ruling  that 
gas-filled  lamps  could  not  be  used  in  flour  mills.  We  found 
they  had  no  particular  information  as  to  what  the  risk  was  sup- 
posed to  be.  They  knew  that  the  gas-filled  lamps  were  hotter 
and  for  that  reason  considered  it  safer  not  to  use  them.  So  we 
started  investigations.  Our  first  experiments  showed  that  we 
could  get  explosions  by  breaking  any  of  the  three  kinds  of  lamps, 
gas  filled,  vacuum,  or  carbon — the  only  exceptions  were  in  the 
case  of  the  small  sizes  of  carbon  and  vacuum  lamps  (below  30 
watts) — no  explosion  occurred.  So  it  doesn't  look  as  if  there 
is  any  question  of  ruling  against  any  particular  type  of  lamp. 
Now,  in  our  present  experiments  we  are  using  a  hot  plate.  You 
have  probably  seen  the  ordinary  hot  plate  that  is  used  under 
chafing  dishes,  etc.  This  is  connected  up  with  a  thermo-couple. 
We  had  trouble  making  the  connections,  which  has  held  up  the 
work  somewhat.  With  this  plate  we  found  that  we  could  not 
get  incandescence  below  500  degrees  Centigrade.  We  have  no 
lamps  that  show  over  356  degrees  Centigrade.  So  we  have  been 
trying  to  get  all  the  information  we  could  as  to  fires  started  b) 
lamps  and  up  to  the  present  time  haven't  been  able  to  get  any  in 
our  experimental  work,  though  because  of  the  large  number  of 
instances  reported  it  seems  probable  that  we  may  succeed  if  the 
bulb  is  raised  to  a  high  temperature  by  some  unusual  condition. 

Though  not  directly  in  line  with  this  question,  it  might  be  a 

good  thing  to  realize  that  mill  owners  are  spending  a  great  deal 

of  money  for  very  poor  lighting.  Take  an  ordinary  vacuum 
lamp — your  light  goes  out  in  this  way  (indicatin  J  broken 

line  curve). 

Practicall}    all    horizontal    at    the    -i<le>.      That    is    the    way 

they  arc  burning  them,  directing  no  light  down  here  (indi< 

ing  below  tin-  hull)).     If  the)  put  ou  a  shade  of  some  kind,  the 


light  is  re-directed  and  you  get  it  where  you  want  it.  (Fig.  2. 
Solid  line  curve.  The  dot-and-dash  line  shows  bowl  frosted 
lamp  with  shade.)  It  seems  to  me  that  this  point  should  be 
taken  up  with  them.  They  might  be  able  to  use  smaller  lamps 
and  there  would  be  less  danger  from  broken  bulbs.  Vapor 
proof  fixtures  are  made  with  a  shade,  so  they  are  at  no  dis- 
advantage from  that  standpoint.  I  noticed  one  particularly 
bad  case  in  Weehawken,  N.  J.  A  man  had  hung  a  100  watt 
light  in  front  of  the  scale  beam  so  that  the  light  was  between 
the  scale  and  his  eyes.  If  he  was  unable  to  see  the  scale  I 
suppose  he  would  hang  a  larger  light  in  the  same  place.  Mr. 
Reed  spoke  in  his  paper  about  having  surfaces  which  would 


Fig.   2. 
Showing   distribution  from  bare  lamp  ami  with  shade. 

not  collect  the  dust.  That  was  one  point  I  wanted  to  ask 
him  about.  We  all  know  you  cannot  get  any  particular  angle 
which  won't  colled  some  dust.  Is  there  any  particular  angle 
to  which  you  referred,  Mr.  Recti  ? 

Mr.  REED — Of  course  the  angle  of  repose  of  dust  will 
depend  on  tin-  nature  of  the  dust  accumulated.  I  made  that 
statement  more  or  less  as  a  means  of  preventing  large  dust 
accumulations  from  forming.  For  instance,  in  some  points 
of  an  elevator  as  much  as  six  inches  of  dusl  can  accumulate, 
sample,  on  window  ledges.  It  they  were  built  up  this 
u;i\  (indicating  a  Bloping  surface)  instead  of  straight  out, 
dusl  could  accumulate. 

68 


Mr.  FOX — I  supposed  that  was  what  you  meant.  Xow 
only  one  other  thing — I  think  probably  most  of  you  have  seen 
the  questions  made  up  at  the  last  meeting.  I  think  we  have 
asked  an  awful  lot  of  questions.  However,  we  hope  we  shall 
be  able  to  get  some  of  them  answered. 

Dr.  BAILEY— Did  I  understand  you  to  say  that  the  hottest 
temperature,  even  at  the  surface  of  these  globes,  is  356  degrees 
Centigrade?  Of  course  the  temperature  on  the  inside  would  be 
considerably  higher? 

Mr.  FOX — The  actual  temperature  of  the  glowing  filament 
of  the  Mazda  "B"  lamp  is  about  2200  degrees,  the  Mazda  "C" 
lamp  about  2800  degrees  and  melting  point  of  tungsten  about 
3400  degrees  Centigrade. 

Dr.  BAILEY — I  don't  understand  just  what  is  meant  by 
"B"  type  and  "C"  type. 

Mr.  FOX — The  "B"  lamp  is  our  vacuum  lamp.  The  "C" 
lamp  is  filled  with  nitrogen  or  argon. 

Mr.  PRICE — We  understand.  Mr.  Fox,  that  in  the  hot 
plate  tests  the  minimum  temperature  was  540  degrees? 

Mr.  FOX— Between  500  and  550. 

Mr.  PRICE — So  we  have  a  difference  of  200  degrees. 

Mr.  BODNAR — About  what  was  the  color  of  the  glowing 
plate? 

Mr.  F(  )X — 1  haven't  seen  the  plate.  Haven't  been  able  to 
get  out  to  Cleveland  since  tiny  had  it  connected  up.  I  am 
going  out  in  about  two  weeks. 

Mr.  BODNAR— Did  your  firm  also  make  temperature 
observations  on  the  surface  of  the  ordinary  Mazda  lamp  bulb? 

Mr.  I;<  »X  The)  made  some  tests  with  nitrogen  filled 
bulbs. 

Mr.  DEDRICK      Would  there  be  any  objection  to  making 
the  globe  cylindrical  in  form  and  having  on  the  top  a  non- 
conducting   material,   as    asbestos,   between    the    s 
that  the  dust   falling  on  the  top  of  the  bulb  would  not  be 

heated?    That  would  do  away  with  the  angle  <>t'  the  globe. 

Mr.  F(  )\  I  think  possibly  I  can  explain  that.  The 
Ma/da  "i  "  lamp  i^.  of  COUrse,  the  hottest.  The  bulb  i^ 
filled   with  an  inert  gas  and   m   the  neck  of  the  bulb   we  ha. 

m 


mica  disk  (A),  which  keeps  the  stem  (B),  as  shown  in  figure 
3,  quite  cool.  The  hottest  point  of  your  bulb  is  at  C,  figure  3. 
Our  reason  for  putting  in  that  disk  is  to  keep  the  base  and 
also  the  stem  cool.  We  have  to  have  a  special  glass  for  this 
stem,  because  we  find  that  other  glasses  above  certain 
temperatures  become  conductors  and  the  glass  is  broken 
down  around  the  leads  and  gradually  you  get  a  leak.  If 
the  bulb  were  cylindrical,  the  disc  would  not  be  as  effective 
in  keeping  the  hot  gas  away  from  the  stem  seal. 

We  make  tubular  lamps  for  moving  picture  machines.  The 
blackening  takes  place  in  this  lamp  up  above  the  filament  as  the 
lamps  are  burned  tip  up.  Practically  all  the  regular  lamps 
are  burned  tip  down  and  there  would  be  no  way  of  protecting 
the  stem. 

Mr.  DEDRICK— I  had  reference  to  the  settling  of  the  dust 
on  the  top  of  the  lamp. 


Fig.  3. 
Mazda  "C"  type   lamp. 

Mr.  FOX — You  see  all  of  these  bulbs  will  be  blown  by 
machinery  and  1  don't  know  whether  we  would  be  able  to 
increase  the  angle. 

Mr.  BATES — I  understand  from  the  drawing  (Fig.  2)  that 
the  radiant  energy  is  given  out  in  about  that  shape.  Natur- 
ally heat  would  be  given  out  in  aboul  the  same  way.  Have 
you  considered  the  idea  of  an  inverted  pear  shaped  globe 
where  the  chance  for  dust  collection  would  be  on  the  taper, 
and  above  that  some  form  of  energy  disbursement  so  that 
the  pari  where  it  went  through  the  globe,  instead  of  being  an 
angle  like  this  would  be  an  angle  like  this  and  no  chance  for 
the  du^t  to  settle?     It  appears  the  dust  would  collect  up  here 

70 


and  you  could  guard  against  that,  possibly,  by  having  an  air 
space  in  there. 

Mr.  FOX — Well,  that  particular  lamp  is  a  vacuum  lamp. 
Is  that  what  you  are  referring  to,  or  are  your  referring  to  a 
gas  filled  lamp?  I  am  afraid  that  this  bulb  shaped  like  a 
strawberry,  with  the  filament  at  the  small  end,  would  not  be 
practical  for  manufacturing  reasons. 

Mr.  BATES — Another  thing  occurred  to  me — that  the  in- 
creased temperature  of  the  gas  filled  lamp  is  probably  due  to 
the  fact  that  you  get  both  the  heat  of  radiation  and  conduction. 

Mr.  FOX— Yes. 

Dr.  BAILEY — 356  degrees  was  measured  om  the  surface 
of  the  bare  bulb.  Wouldn't  that  amount  to  more  if  the  bulb 
were  coated  with  dust  ?  Wouldn't  that  dust  coating  hold  in 
the  heat? 

Mr.  FOX — Of  course  with  a  heavy  coating  the  temperature 
rises. 

Mr.  REED — Can  you  tell  me  in  general  figures  just  what 
per  cent  of  the  present  bulb  would  be  covered  with  dust?  I 
judge  about  60  to  70  per  cent. 

Mr.  FOX — Probably.     Not  much  less. 

Mr.  REED — In  other  words  the  light  will  be  decreased  at 
the  same  time. 

Mr.  FOX — Yes,  cut  down  40  to  50  per  cent  in  two  or  three 
week-  simply  by  dust  collection.  If  we  put  a  vapor  proof 
fixture  around  the  bull)  there  you  have  your  straight  walls  and 
less  chance   for  the  dust   to  collect. 

Dr.  DUVEL  That  would  also  protect  the  bulb  from  dust  ;t 
great  deal. 

Mr    FOX- n 

Dr.  DUVEL  The  accumulation  there  would  be  slight  and 
they  would  clean  it  off  From  time  to  time. 

Mr.  McCOLLAM  \l>out  what  percentage  decrease  in 
illumination  is  caused  by  a  vapor  proof  glob 

Mr.    FOX     Hardly  appreciable  as  the  globes  are  of 

glass. 

n 


Mr.  BODXAR — Do  you  think  it  would  be  necessary  to  have 
a  vapor  proof  globe  if  you  have  a  shade?  I  believe  there  is 
a  natural  rise  of  air  through  the  top  opening  of  the  shade,  so 
that  no  dust  would  settle  when  using  a  shade.     Is  that  the  case? 

Mr.  FOX — From  a  question  of  protecting  the  lamp  from 
breakage  you  want  all  the  protection  you  can  get. 

Mr.  HELMKAMP— Don't  you  think  it  would  be  possible 
to  equip  this  globe  with  some  sort  of  shade  and  have  the  whole 
thing  together? 

Mr.  FOX — They  do  make  such  a  shade  and  globe.  The  only 
thing  we  want  to  be  sure  of  is  that  all  these  precautions  are 
necessary. 

Mr.  BRADY — Just  why  did  the  insurance  companies  rule 
against  the  nitrogen  lamp? 

Mr.  FOX — They  knew  it  was  hotter  and  desired  to  be  on 
the  safe  side.  They  had  run  no  tests,  but  told  us  they  would  be 
glad  to  have  us  do  so. 

Mr.  BROWN — How  long  was  that  dust  accumulation  allowed 
to  remain  on  the  bulb  in  making  the  tests? 

Mr.  FOX — Only  one  hour  on  the  one  I  saw,  as  the  test  was 
made  just  before  I  was  leaving  and  I  didn't  have  time  to  wait 
any  longer.  In  some  cases  it  was  allowed  to  remain  on  four 
and  five  hours. 

Mr.  BROWN — I  was  wondering  what  difference  that  would 
make.  Of  course  in  some  of  the  plants  it  is  allowed  to 
accumulate  for  months  and  becomes  baked  on. 

Mr.  BODNAR— In  one  of  the  elevators  that  I  visited  I  found 
a  75  watt  Peerless  Mazda  in  the  dust  on  the  floor.  A  little 
dust  had  collected  on  it  and  I  added  a  little  more.  In  less 
than  two  minutes  it  started  to  smoke  and  I  don't  think  I  had 
over  1/32  of  an  inch  <  f  dust  on  it.     It  doesn't  take  very  long. 

Mr.  FOX— We  have  no   difficulty   doing  that   at   all.   but    we 

ean't  get  the  dust  to  burn.     Another  possibility  in  some  of  these 

cases    where    they    think   they    have    seen    lire    is    that,    when   you 

dusl   charred  on  the  bulb  you  see  tin-  filament   through  it 

and  it  appears  as  if  the  dusl  were  glowing. 

Mr.    PRICE      I    wanted    to   ask    Mr.    Fox    if    there    have    been 

any   further  developments  since  our  conference  in    New   York 

about   a   month  ago  ? 

11 


Mr.  FOX — Mr.  Dows,  I  believe,  has  gotten  the  machine  run- 
ning in  which  he  is  going  to  have  the  lamps  surrounded  by  a 
dust  cloud  for  a  long  time. 

Mr.  PRICE — For  the  information  of  our  men  I  was  wonder- 
ing if  you  could  tell  us  what  plans  the  lamp  companies  have 
regarding  future  work. 

Mr.  FOX — Our  present  plans  are  to  keep  on  experimenting 
until  we  can  make  definite  suggestions  to  the  fire  underwriters. 

Mr.  DEDRICK — I  will  make  a  statement  in  regard  to  a 
lamp  being  lowered  into  a  bin  and  lying  for  a  while  covered  up. 
That  happened  in  Chicago  at  one  of  the  plants.  It  just  hap- 
pened at  the  time  of  my  visit  and  while  I  was  talking  to  the 
men.  I  had  made  a  point  in  regard  to  the  possibility  of  having 
fires  and  explosions  from  electric  lamps.  A  man  came  toward 
us  with  a  shovel  which  was  a  mass  of  coals  with  an  electric  lamp 
which  was  broken.  (This  was  ground  feed,  oats,  I  believe.) 
It  was  on  the  point  of  flaming,  that  is,  it  was  all  live  coal.  It  was 
found  that  one  of  the  fellows  had  lowered  a  lamp  into  a  bin 
to  see  how  much  was  in  the  bin.  then  left  the  lamp  there  in 
about  two  feet  of  dust  or  material.  Someone  smelled  smoke  and 
found  the  lamp  burning,  pulled  it  up,  and  went  down  into  the  bin 
and  discovered  the  mass  of  coals,  which  were  shoveled  out  to 
remove  all  the  fire.  The  superintendent  was  there  and  it  empha- 
sized the  dangers  of  being  negligent  in  using  lights,  putting  them 
down  into  bine  and  leaving  them.  I  don't  think  that  lamp  was 
down  there  more  than  half  an  hour  or  possibly  three-quarters  of 
an  hour. 

Mr.  FOX — I  don't  think  there  is  any  doubt  about  that  occur 
ring.     We  have  even  had  a  case  of  a  man   who  took  a   lamp 
and  put   it  in  the  bed  to  keep  his  feet  warm   (it  was  a  cold  night 
in  winter),  and  it  burned  up  the  bed.     (Laughter.) 

Mr.  BATES-  A  circumstance  jusl  came  to  my  mind,  though 
not  actually  along  the  lighting  question,  of  an  incident  that 
occurred  in  an  elevator  not  a  hundred  miles  from  here,  of  the 
overloading  of  an  electric  circuit  by  connecting  an  electric  mois- 
ture machine  onto  an  ordinary  lighting  circuit.  This  mr 
compartment    machine,   each   compartment    requiring  about 

ampere^    of   electricity    at     1 1 » >    volts.       That    would    be    equivalent 

to  something  like  75,  25  watt  lamps,  which,  of  course,  is  greatly 
overloading  the  circuit  and  endangering  the  elevator  from  fire 
due  to  the  heat  generated  in  the  circuit.     That  is  just  one  c 


that  we  have  seen,  but  as  electrically  heated  moisture  machines 
come  into  use  more  generally,  it  is  something  that  we  should 
look  into  very  fully.  The  machines  should  be  properly  connected 
by  wires  of  sufficient  size  to  satisfy  the  underwriters'  code  for 
electric  circuits. 

Mr.  HIBBARD— Don't  you  think  a  fuse  plug  there  would 
take  care  of  that,  a  fuse  to  melt  at  about  8  or  10  amperes? 

Mr.  BATES — A  10-ampere  fuse  would  be  of  no  use  on  a  cir- 
cuit where  20  amperes  were  required.  Then  some  one  would 
probably  substitute  a  tenpenny  wire  nail  for  the  fuse. 

Dr.  DUVEL — That's  the  difficulty.  In  those  cases,  heavy 
wire  is  often  used.  As  there  are  more  of  these  machines  coming 
into  use  this  is  an  interesting  question.  Is  there  further  discus- 
sion of  this  matter?  This  question  of  electric  lighting  in  eleva- 
tors is  undoubtedly  a  very  important  one.  There  have  been 
some  interesting  developments  in  the  last  six  months  and  we 
feel  that  in  another  six  months'  time  something  will  come  out  of 
this.  If  there  is  no  further  discussion  on  this  we  will  pass  to 
the  next  paper. 

Mr.  Riley  will  give  us  some  of  his  experiences  in  the  presenta- 
tion of  dust  explosion  work  before  high  school  students. 

"PRESENTATION   OF   DUST   EXPLOSION   WORK   BE- 
FORE HIGH  SCHOOL  STUDENTS." 

By  Mr.  E.  L.  Riley. 

Mr.  Chairman :  In  February,  while  in  Springfield,  Ohio, 
I  visited  the  two  high  schools  there  and  presented  our  work, 
and  seeing  how  well  it  was  received  by  both  faculty  and  students, 
I  decided  to  visit  the  high  schools,  wherever  it  was  possible  to 
do  so,  providing,  of  course,  that  it  did  not  interfere  with  my 
other  work  in  any  way.  In  presenting  this  work  I  give  a  short 
talk  on  conditions  necessary  to  produce  a  dust  explosion  and 
then  go  on  to  tell  what  the  United  States  Grain  Corporation,  co- 
operating with  the  lr.  S.  Department  of  Agriculture,  is  doing  to 
eliminate  these  dangerous  conditions  in  the  mills  and  elevators 
of  this  country.  After  this  brief  talk  I  give  the  demonstrations, 
Using  various  dusts,  such  as  elevator  dust,  flour,  corn  starch, 
wood  dust,  spice  dusl   ( from  spice  mills)  and  pulverized  sugar, 

and  after  giving  the  demonstrations  1  try  to  answer  any  ques- 
tions that  may  be  asked.  In  one  school  I  visited  I  discovered 
an    Instructor    who   evidently    had    never    had    an    opportunity   to 

74 


read  any  of  our  literature  pertaining  to  grain  dust  explosions  and 
was  still  instructing  his  classes  according  to  the  old  form  of 
text  books  that  teach  dust  explosions  in  mills  and  elevators  are 
caused  by  spontaneous  combustion.  This  instructor  informed 
me  that  explosions  in  mills  and  elevators  had  been  discussed  in 
the  class-room  the  week  previous  to  my  visit  to  the  school  and 
he  had  informed  the  students  that  they  were  due  to  spontaneous 
combustion.  He  advised  me  that  he  would  be  glad  to  use  any 
literature  that  the  Department  had  in  his  work  in  the  school  and 
he  hoped  to  be  able,  on  receiving  this  literature,  to  go  more 
deeply  into  the  subject  of  dust  explosions.  It  may  be  well  to 
mention  here  the  fact  that  every  principal  and  instructor  I  have 
met,  while  visiting  the  schools  on  this  work,  has  stated  his  in- 
tention of  following  up  this  work  and  has  asked  for  bulletins 
and  publications  on  the  subject,  in  order  to  prepare  himself  to 
give  the  information  to  his  students.  I  have  experienced  no 
difficulty  in  arranging  for  the  presentation  of  the  work  at  the 
various  schools  visited,  but  always  found  the  faculty  only  too 
glad  to  allow  me  the  time  I  needed  to  give  the  talk  and  demon- 
strations. In  some  schools  visited  I  have  been  ushered  into  one 
of  the  class-rooms  by  the  principal,  introduced  to  the  instructor 
in  charge  and  have  then  introduced  myself  and  my  work  to  the 
students,  but  in  a  few  of  the  schools  I  have  been  received  on  a 
more  elaborate  scale,  one  school  in  Buffalo  going  so  far  as  to 
have  the  school  orchestra  of  eighteen  or  twenty  pieces  take  their 
places  on  the  stage  with  me  and  render  a  few  selections,  both 
before  and  after  the  talk  and  demonstration.  I  am  sorry  to 
that  1  have  not  had  that  experience  very  often.  The  attend- 
ance at  this  one  meeting  numbered  1,500  students  and  my  au- 
dience mver  ran  under  80  students  at  any  time.  At  another 
Buffalo  school  I  visited,  the  students  endeavored  to  show  their 
appreciation  of  the  work  and  my  efforts  in  their  behalf  by  having 
the  cheer  leader  step  onto  the  stage  where  he  led  the  students  in 
the  school  yell,  ending  with  "Yea,  Riley."  \s  the  attendance 
numbered  from  800  t<.  1.000.  it  was  some  "Yea."  Many  qu 
tions  wire  asked  by  the  faculty  and  students  in  regard  to  dust 
explosions  and  their  prevention,  and  I  believe  from  the  inte: 
taken  in  this  work,  that  the  time  given  to  it   was  not   wasted,   for 

in  my  opinion  the  best  way  t<   spread  this  work  of  (\u  sion 

prevention  is  to  bring  it  before  the  faculty  and  students  in  high 
schools,  an,i  if,  t'ur  lack  of  funds  men  are  not  available  to  | 

sent  it.  films  that  we  now  have  could  he  turned  oxer  to  tin-  State 
educational    authorities   ami    through    them    could    hi-    sent    to   the 

7? 


various  high  schools  in  that  State,  giving  special  attention  to 
schools  in  sections  where  the  grain  or  milling  interests  are  largely 
interested.  I  believe  that  by  doing  this  the  work  will  have  a 
far-reaching  effect,  and  before  many  years  have  passed  we  will 
have  mills  and  elevators  that  will  be  explosion  proof,  or,  in  other 
words,  free  from  dust. 

Dr.  DUVEL — This  has  brought  out  some  very  interesting  ex- 
periences on  our  educational  campaign  that  has  been  carried  on. 
You  will  probably  wonder  why  the  Grain  Corporation  got  off 
into  this  phase  of  dust  explosion  work.  Of  course,  when  we 
first  started  it  was  primarily  to  protect  our  own  interests,  but 
we  felt  that  as  we  were  co-operating  with  the  Department  of 
Agriculture  we  could  not  be  severely  criticised,  and  as  Mr.  Riley 
has  stated  some  good  will  come  out  of  it,  even  though  the  De- 
partment of  Agriculture  is  not  going  to  be  in  position  to  follow 
this  work  up. 

Mr.  PRICE — Special  motion  picture  films  of  a  popular  nature 
are  now  in  preparation  by  the  Department.  They  will  be  avail- 
able for  general  use  and  can  be  circulated  among  the  schools 
and  colleges.  They  have  been  prepared  with  a  view  to  meeting 
the  need  suggested  by  Mr.  Riley. 

Dr.   DUVEL — Is  there  any   further  discussion? 

Dr.  BROWN — It  seems  to  me  that  the  question  of  presenta- 
tion work  in  High  Schools  better  be  carried  just  a  little  bit  fur- 
ther and  take  it  in  the  colleges.  I  might  state  that  I  recently  had 
the  privilege  of  addressing  a  college  audience.  The  president 
introduced  me  and  we  put  on  our  performance  and  I  feel  that 
it  was  worth  while  ;  it  was  well  received.  1  feci  that  agricultural 
colleges  at  least  would  be  very  much  interested  in  the  discussion 
of  this  question  and  particularly  as  related  to  the  field  work  and 
threshing  end  of  it,  and  that  the  milling  colleges,  where  they 
give-  milling  courses,  would  be  interested.  It  might  also  be 
taken  up  in  other  branches  of  college  activity  and  be  extended 
by  the  films  which  we  are  having  prepared  at  the  present  time. 

Dr.  DUVEL  1  agree  fully  with  Dr.  Brown.  By  getting  this 
into  agricultural  colleges,  you  get  in  direct  contact  with  those 
who   intend    following  this   line   of    work.      1    believe   it    would   be 

a  tine  thing  if  tin-   Department  could   prepare  something  very 

definite  for  a  scries  of  lectures  for  the  agricultural  colleges  to 
go  right  into  or  to  he  made  a  part  of  their  courses,  and  arrange 
to  furnish  them  film-  or  loan  them  films  or  slides,  or  something 

to  demonstrate. 

76 


Dr.  BAILEY — I  think  they  should  also  go  to  a  number  of 
engineering  departments.  We  are  training  a  number  of  men  in 
engineering  aspects  of  cereal  work  and  those  men  do  not  get 
much  chemistry.  Sometimes  they  go  away — leave  college  with  a 
bad  misconception.  Then  we  are  increasing  our  technical  de- 
partment. They  are  sending  men  where  these  films  would  be 
very  useful.  They  are  keen  for  that  sort  of  thing  and  we  are 
looking  for  them  all  the  time. 

Dr.  BROWN— I  think  that  Dr.  Bailey's  idea  might  be  ex- 
tended not  only  to  include  those  men  who  are  getting  into  cereal 
work,  but  to  all  types  of  industrial  work. 

Dr.  BAILEY — There  are  many  men  who  will  go  into  the 
cereal  industry,  and  I  think  they  should  certainly  be  provided 
with  this  material.  1  think  the  men  who  are  in  college  now 
should  get  this  training. 

Mr.  RILEY — I  think  the  engineering  courses  should  give 
consideration  to  this  work. 

Dr.   DUVEL — Is  there  any   further   discussion? 

Mr.   REED — I   think    the    colleges   should   be    visited   before 
high  schools.     Mr.  Riley  says  that  by  reaching  the  high  schools 
you  reach  them  all,  but  you  reach  them  before  it  would  be  ne< 
sary.     I  doubt   very  much  if  they   would   hold  a   meeting  at  the 
high  school  I  attended;  such  a  man  would  be  at  a  disadvant 

Mr.  RILEY — One  of  the  meetings  I  held  happened  to  be  in 
his  state  and  they  were  very  glad  to  have  me  there.  The  super- 
intendent of  education  informed  me  that  it'  1  could  not  get 
there,  to  send  a  request  to  Washington  that  such  a  demonstra- 
tion be  given  and  to  use  his  name  in  this  request. 

Dr.  DUVEL-  There  i^  no  doubt  but  that  people  arc  getting 
more  interested  in  his  subject.  We  have  about  covered  the  dis 
cussion  on  this  subject;  it  is  now  after  twelve  and,  I  believe,  w e 
had  better  adjourn  until  this  afternoon.  1  am  glad  to  announce- 
that  Mr.  Barnes  will  attend  our  meeting  this  afternoon  and  give 
us  his  views  of  the  importance  of  this  work. 

Adjourned  until  1  :30  p.  m. 


FRIDAY  AFTERNOON  SESSION 

April  23,  1920. 

Dr.  H.  H.  Brown,  Presiding. 

Results  of  Work  in  Various  Districts. 

Dr.  BROWN — The  meeting  will  please  come  to  order.  This 
afternoon  we  expect  to  have  a  discussion  of  some  of  the  results 
of  our  actual  work  in  the  field  during  the  past  year,  and  more 
particularly  the  results  of  our  inspection  work.  As  you  know, 
the  work  of  the  Department,  in  co-operation  with  the  Food 
Administration  last  year,  was  divided  into  five  districts.  On  ac- 
count of  curtailing  some  of  the  activities  and  having  cut  down  the 
force,  in  the  present  campaign  the  country  was  divided  into  three 
districts.  We  will  now  hear  reports  of  the  results  of  work  in 
these  different  districts,  first  in  the  East,  then  in  the  Central  North- 
west and  then  the  Pacific  Coast.  We  will  have  all  these  reports 
and  then  follow  with  the  discussion  covering  the  entire  country, 
rather  than  taking  the  various  districts.  I  take  this  opportunity 
to  call  upon  Mr.  H.  R.  Brown,  who  has  charge  of  the  Eastern 
District. 

REVIEW  OF  WORK  IN  EASTERN  DISTRICT 

By  H.  R.  Brown. 

Mr.  BROWN — Mr.  Chairman  :  I  had  prepared  a  regular  paper 
on  this  subject  showing  statistics  by  grade  and  number,  but  as 
one  man  who  came  into  the  office  said,  there  arc  "white  lies, 
black  lies,  and  statistics",  I  therefore  tore  that  paper  up  and  you 
will  have  to  take  my  word.  The  plants  visited  in  the  east  were 
mostly  those  carrying  Grain  Corporation  stocks.  I  think  our 
best  results  have  been  obtained  by  the  use  of  our  miniature  ele- 
vator and  the  cheese-cloth  demonstration.  We  hope  to  be  able 
to  give  you  a  demonstration  later  in  the  afternoon.  I  think  we 
have  this  elevator  demonstration  down  pretty  fine  now  and  quite 
an  improvement  on  our  former  demonstrations.  1  might  also  call 
your  attention  to  the  method  of  giving  the  cheese  cloth  demon- 
stration,— another  improvement  which  I  discovered  about  two 
wet'  -  balls  where  we  have  held  meetings  with  an 

attendance  of  about  1000  people,  I  noticed  that  they  had  some 
trouble  in  seeing  jusl  how  the  lire  is  started.  1  found  thai  by 
putting  a  larger  amouni  in  the  cheese  cloth  and  tying  it  on  the 

end  of  a  pole  and  then  shaking  the  pole  over  the  ilame,  that  this 
makes  the  demonstration  much  more  effective.     There  are  two 

78 


other  point-  I  want  to  bring  out  in  taking  up  the  results  of  this 
work,  and  that  is,  demonstrations  given  before  fire  departments 
and  the  high  schools.  Mr.  Riley  told  you  about  the  high  school 
demonstrations,  and  I  think  that  matter  was  thoroughly  discussed. 
It  is  agreed  that  it  would  be  a  fine  thing  to  bring  this  matter 
to  the  high  school  students  and  also  to  the  engineering  societies 
in  the  colleges  or  technical  schools  of  the  country.  I  think  our 
men  made  special  efforts  in  different  cities  to  take  up  this  matter 
with  the  various  fire  departments.  In  this  way  we  have  ob- 
tained the  co-operation  of  these  men  in  reporting  fires  in  mills 
or  elevators.  On  certain  occasions  we  have  been  able  to  get  to 
the  scene  of  the  fire  right  with  the  company,  the  Chief  taking 
the  men  to  the  fire  in  his  car  and  they  were  there  to  see  what 
was  going  on.  This  happened  to  Mr.  Riley  and  Mr.  Helmkamp. 
They  happened  to  be  at  the  fire  house  when  the  alarm  came  in. 
In  one  case  the  Chief  called  up  the  man  at  the  hotel  and  picked 
him  up  on  the  way.  They  have  been  taught  that  it  is  especially 
dangerous  to  turn  a  stream  of  water  into  a  cloud  of  dust.  They 
have  also  been  taught  that  it  is  to  their  advantage  to  visit  the 
plants  frequently  and  endeavor  to  impress  upon  the  employes 
the  necessity  of  keeping  the  place  clean,  not  only  for  their  own 
protection  but  also  in  the  case  of  the  firemen  who  would  be 
called  upon  to  fight  the  fire.  There  is  one  special  feature  I  want 
to  call  to  your  attention.  Mr.  Witmer  is  the  hero  in  this  case. 
One  elevator  down  in  Philadelphia  we  have  been  after  them  for 
three  years  to  put  in  an  improved  lighting  system.  They  have 
been  using  open  gas  jets  in  this  plant,  so  the  foreman  said,  for 
forty  years  at  least.  \Yc  have  called  this  to  the  attention  of  the 
manager,  the  foreman,  the  superintendent,  and  even  taken  the 
matter  to  the  railroad  company  and  the  owners  of  the  elevator, 
and  they  said  their  plant  had  been  operating  for  forty  years  and 
nothing  ever  happened  We  had  just  about  given  up  this  case. 
when  Mr.  Witmer  seemed  to  get  on  the  right  side  of  the  manage- 
ment. T  am  now  pleased  to  say  that  an  improved  lighting  system 
has  been  installed  In  this  plant,  which  is  one  of  the  results  for  im- 
proving plants  in  the  eastern  district.  A  small  number  of 
plosions  have  occurred  in  the  east,  Later  on  we  are  going  to 
take  Up  several  minor  explosions,      two  plants  in  Buffalo,  and  the 

Cincinnati  explosion.  Mr.  Riley  will  tell  yon  of  the  explosion  at 
the  Spice  Works  in  Cincinnati  and  at  the  II.  O.  plant  in  Buffalo. 
Mr.  Helmkamp  will  give  you  a  short  account  of  the  explosion  in 
the  Curtiss  plant  in  Buffalo.  Mr.  Price,  in  his  summary  of  the 
work-   for  the  entire  country,  will  uri\i-  you   some  figures  and 

70 


statistics,  I  believe,  on  the  results  of  inspection  work,  showing 
improvement  in  the  condition. 

Dr.  BROWN — I  am  sure  this  is  an  interesting  report.  Before 
we  go  on  with  a  discussion  of  it,  I  take  pleasure  in  calling  upon 
Mr.  Brady  to  give  us  the  result  of  his  inspections  of  the  central 
and  northwestern  district. 

REVIEW  OF  WORK  IN  CENTRAL  AND  NORTH- 
WESTERN DISTRICTS 

By  P.  E.   Brady. 

Air.  BRADY — Mr.  Chairman:  Our  work  has  been  confined 
mostly  to  the  Grain  Corporation  plants.  We  have  a  large  area 
to  cover  and  it  was  our  object  to  visit  these  plants  at  least  once  a 
month  and  make  inspections  of  them.  In  doing  that  we  found 
we  could  devote  but  little  time  to  outside  work.  However,  we 
used  to  get  ten  days  out  of  every  month  whereby  we  could  go 
to  the  various  outlying  plants,  and  we  invariably  tried  to  put 
on  a  show  for  the  benefit  of  the  larger  mills.  We  always  carried 
our  pictures  with  us  and  invariably  found  a  place  around  the 
mill  where  we  could  give  a  demonstration  and  put  on  the  pictures. 
We  found  that  the  millers  were  very  grateful  for  this  work,  and 
believe  that  we  did  considerable  good  in  educating  the  men  along 
the  dust  explosion  hazards.  We  recieved  very  good  co-operation 
from  the  fire  departments  through  that  portion  of  the  country 
also,  and  in  Minneapolis  the  Chief  now  has  the  men  make  a 
regular  inspection  of  the  elevators  in  that  city,  due  primarily  to 
the  work  that  we  have  started  there.  We  had  occasion  to  in- 
vestigate two  explosions  in  that  territory, — one  was  the  Kansas 
City  explosion  in  the  Murray  Elevator,  the  other  an  aluminum 
goods  manufacturing  company  plant  at  Manitowoc,  Wisconsin. 
In  connection  with  the  small  meetings  which  we  have  had  at  the 
various  small  outlying  plants,  there  has  also  been  put  on  in  that 
district  probably  15  or  20  large  meetings  in  the  larger  cities,  such 
as  Chicago,  Milwaukee  and  Minneapolis,  where  Dr.  Brown  or 
Mr.  Price  have  made  addresses.  No  doubt  Mr.  Price  has  the 
figures  and  knows  the  number  of  meetings  held  in  that  territory, 
and  as  for  making  the  summary,  Mr.  Price  can  fix  Up  the  figures 
on  that  1  believe.    We  have  made  around  855  inspections  in  thai 

territory   altogether    since    the   drain    Corporation    took    over   this 

work.    Thai  completes  the  report   for  the  northwestern  district. 

Dr.  BROWN  Before  we  go  on  t<>  the  next  report,  I  helicvc 
it  would  he  interesting,  Mr.   Brady,  if  you  could  tell  us  some 

so 


specific  instances  of  improvement  that  has  been  brought  about 
in  your  district  as  a  result  of  the  inspection  work. 

Mr.  BRADY — Well,  I  will  take  Chicago,  for  instance.  I  just 
had  a  letter  from  Mr.  Farrell,  in  charge  of  the  inspection  work 
there  for  the  Grain  Corporation,  and  in  that  letter  he  said  that 
he  was  very  pleased  to  note  that  of  late  the  reports  which  have 
been  coming  in  from  us  had  been  showing  a  marked  improvement 
in  that  a  good  many  houses  that  were  formerly  in  the  "B" 
class  had  been  raised  to  "A."  I  might  say  that  in  general  that 
covers  the  entire  northwestern  and  central  district.  There  is  no 
question  but  that  the  houses  in  Minneapolis  have  been  improved, 
and  one  of  the  insurance  men  was  remarking  to  me  along  those 
lines,  just  the  other  day,  that  since  we  started  the  work  up  there 
the  elevators  had  been  gradually  improved,  and  he  felt  that  it  was 
in  a  large  measure  due  to  the  educational  work  that  had  been 
done  in  the  district. 

Dr.  BROWX — Of  course,  we  realize  that  the  greatest  amount 
of  grain  in  this  country  is  handled  through  the  Middle  West 
and  works  east,  and  some  of  us  who  are  in  the  East  sometimes 
forget  that  they  have  grain  on  the  Pacific  Coast,  and  that  they 
have  problems  out  there,  so  that  it  has  been  necessary  to  extend 
our  work  to  that  section  as  well  as  to  others.  Mr.  McCollam, 
who  has  had  charge  of  the  work  in  that  section,  will  now  tell  us 
something  of  the  results  obtained  there. 

REVIEW    OF    WORK    IX     PACIFIC    DISTRICT. 
By  M.    E.    MCCOLLAM. 

Mr.  Chairman:     [n  making  this  report.  I  just  want  to  Speak 
very  briefly  about  four  things:     First,  the  inspection  work;  - 
ond,  the  very  beneficial  educational  tour  on  which   Dr.  Brown 
was  associated  with  us  in  our  district;  third,  the  i  .'ion 

which  WC  have  had  throughout  our  whole  district   with  the  St 
Industrial  Accident  Commission;  fourth,  the  interest  which  other 
manufacturers  and  industries  have  taken  in  our  work.     In  re- 

I  to  the  inspection  work.  Mr.  Bodner  and  myself  did  all  of 
that,  and  I  am  sure  that  I  can  report  an  improvement  in  all  of 
the  plants  on  the  Pacific  Coast  that  needed  improvement.     Be- 
side- giving  attention  to  the  Grain  Corporation  stocks  in 
which,  of  course,  always  came  •"  concentrated  our  atten 

Hon  on  the  mills  and  elevators  which  particularly  needed  clean- 
ing and  which  needed  improvement.     I  might  cite  two  instances 

81 


particularly  in  which  mills  were  improved.  One  of  these  in- 
stances was  a  mill  in  San  Francisco  which  was  improved  from 
a  "CC"  mill  to  a  "BB."  The  other  was  a  mill  in  Seattle  which 
was  improved  from  a  "CC"  mill  to  a  "BA,"  and  I  do  not  think, 
in  this  latter  instance,  there  can  be  very  much  more  desired  in 
the  way  of  improvement.  I  have  no  explosion  to  report — no 
disasters  or  explosions  in  the  Pacific  District.  The  only  in- 
teresting experiences  along  those  lines  I  covered  in  my  talk  this 
morning. 

In  regard  to  Dr.  Brown's  meetings  in  the  Pacific  District,  I 
might  say  that  the  meetings  were  held  at  Spokane,  Tacoma,  Port- 
land, Seattle,  San  Francisco,  Los  Angeles,  Stockton  and  Salt 
Lake  City.  The  one  at  Stockton  was  held  at  the  Sperry  Flour 
Company.  A  very  large  number  of  employees  were  present, 
and  I  think  it  did  a  lot  of  good.  All  of  the  meetings  were  very 
well  attended  with  the  exception  of  the  one  in  Spokane,  although 
that  had  a  very  representative  audience  present.  The  co-opera- 
tion of  the  State  Industrial  Accident  Commission  has  been  very 
complete.  Every  State  in  my  district  has  an  Industrial  Accident 
Commission  or  a  Safety  Department.  In  the  State  of  California 
one  of  their  engineers  has  been  assigned  to  accompany  me  on 
inspections  that  I  made  throughout  the  State  and  this  has  been 
accomplished  in  a  good  many  instances.  He  has  an  automobile 
which  makes  it  very  pleasant  for  me,  and  we  often  tour  around 
and  visit  plants  together.  He  confines  himself  mostly  to  plants 
that  I  want  to  visit.  In  Oregon  the  co-operation  with  the  State 
Industrial  Accident  Commission  there  was  started  by  a  confer- 
ence which  we  had  in  Portland  with  the  State  Labor  Commis- 
sioner and  the  Chairman  of  the  Safety  Board.  Mr.  Bodnar  and 
myself  put  on  a  demonstration  for  them  and  told  them  all  we 
knew  about  dust  explosions.  They  were  very  much  interested 
and  promised  co-operation.  Since  then  that  has  been  carried  out, 
and  on  numerous  inspection  visits  made  by  Mr.  Bodnar  he  has 
been  accompanied  by  a  Safety  Inspector.  In  Washington  that 
has  been  carried  out  also — Mr.  Bodnar  having  been  accompanied 
by  the  Safety  Inspector.  In  Utah  and  Idaho,  the  Safety  Depart- 
ments there  are  in  their  infancy,  but  I  was  promised  in  Idaho 
that  as  soon  as  they  got  their  Safety  Department  working  they 
would  be  delighted  to  arrange  a  tour  through  the  whole  State, 
at  their  expense,  visiting  any  of  the  plants  that  I  designated 
which  I  think  should  receive  attention,  which  I  think  was  a  very 
generous  offer.  In  regard  to  the  interest  in  our  work  in  Cali- 
fornia, I  might  say  that  the  industries  there  are  very  much  in- 

82 


terested.  Just  before  making  this  trip,  I  had  an  interview  with 
Mr.  McBride,  of  the  California-Hawaiian  Sugar  Refineries,  at 
Crockett,  California,  turning  out  1,700  tons  of  refined  sugar  a 
day  and  40  tons  of  powdered  sugar.  Mr.  McBride  said  that  he 
wished  it  might  be  possible  to  have  a  man  stationed  at  the  re- 
finery for  some  months  to  study  the  dust  collection  problems 
that  they  have  there,  and  also  that  it  might  be  possible  for  the 
plant  to  stand  some  of  the  expense,  if  such  was  necessary.  Just 
to  give  you  an  idea  of  the  interest  which  has  been  taken  in  our 
work,  the  other  day  we  had  a  request  from  the  Seattle  Manu- 
facturers Association  for  a  demonstration  and  lecture  before  that 
body.     The  request  came  in  from  the  Secretary. 

Dr.  BROWN — I  certainly  think  that  good  work  has  been  done 
on  the  Pacific  Coast.  We  are  a  long  ways  from  it  but  even 
though  our  work  now  has  to  be  discontinued  I  can  readily  see 
where  somebody  could  tour  all  of  Idaho  at  the  expense  of  the 
State,  and  possibly  spend  a  few  pleasant  months  on  the  Pacific 
Coast  in  the  sugar  industry. 

These  three  subjects  are  now  before  you  gentlemen  for  dis- 
cussion. You  have  all  worked  in  one  or  more  of  the  various 
districts,  and  while  we  are  later  to  have  a  general  discussion 
of  your  personal  experiences  in  making  inspections,  in  which 
I  hope  each  one  of  you  will  take  a  hearty  part,  we  would  like 
to  have  some  discussion  regarding  the  results  of  the  work  in  these 
particular  districts. 

Mr.  PRICE — I  want  to  ask  the  men  in  the  different  districts 
what,  in  their  estimation  or  feeling,  has  been  the  effect  upon 
the  trade  or  industry?  Have  you  been  well  received,  or  have 
you  met  with  any  opposition,  and  what  has  been  the  general  feel- 
ing in  the  respective  districts? 

Mr.  BROWN — I  do  not  believe  there  is  a  single  plant  in 
the  East  where  we  have  had  any  trouble  in  making  the  regular 
inspections  once  a  month  or  every  six  weeks.  Now  and  then 
we  would  get  into  a  discussion  with  the  men  as  to  how  clean 
a  plant  should  be  kept,  but  as  far  as  there  being  any  real  opposi- 
tion or  objection  to  our  work,  there  is  absolutely  none  at  all  in 
the  district.  In  fact,  we  are  commended  Eor  the  work  and  the 
management  is  willing  to  carry  out  every  suggestion  we  make. 
If  we  call  their  attention  to  dust  accumulations,  they  are  generally 
removed  even  before  we  leave  the  house. 

Dr.  BROWN — 1  think  Mr.   Price  had  in  mind  not  the  ques- 

83 


tion  of  objection,  but  of  the  receptivity  of  the  industry  to  the 
work. 

Mr.  PRICE — Yes.  Do  we  get  what  we  want  done,  or  gen- 
erally speaking,  do  you  feel  we  have  gotten  anywhere? 

Mr.  BROWX — Yes,  1  think  the  management  of  the  different 
plants  has  taken  up  this  question  a  little  more  seriously  possibly 
during  the  last  six  months  or  year  than  they  did  at  first.  I  do 
not  know  that  we  are  any  more  welcome  now  than  we  have 
always  been.  They  always  treat  us  very  courteously — the  ele- 
vator superintendent  usually  arranging  to  take  us  to  the  plants 
in  cars.  I  might  call  your  attention  to  the  case  in  Baltimore, 
where  the  elevators  carried  Grain  Corporation  stocks,  and  on 
our  visits  there  the  superintendents  asked  for  our  advice  on  a 
number  of  questions  and  have  carried  out  our  suggestions. 

Dr.  BROWX — I  think  it  might  be  interesting  if  we  would 
know  the  condition  of  the  worst  elevator  in  this  district  and  its 
present  condition. 

Mr.  BROWX — The  worst  case  was  an  elevator  where  they 
were  using  open  gas  flames  in  a  dusty  room.  They  now  have 
installed  the  latest  improvements.  In  another  elevator  on  a 
number  of  visits  we  found  lanterns  being  used  in  the  plant. 
They  have  electric  lights,  but  when  they  start  unloading  or  load- 
ing cars,  the  first  floor  gets  so  dusty  that  they  can't  see  the  electric 
lights,  and  the  man  carries  the  lantern  around  to  find  his  way 
We  have  taken  that  question  up  and  1  do  not  believe  there  is  a 
lantern  used  in  that  plant.  So  practically  all  our  suggestions  have 
been  carried  out  to  the  letter. 

Mr.  BRADY — As  a  whole  we  have  had  very  good  co-operation 
from  the  men.  In  Minneapolis,  the  Chamber  of  Commerce  men 
have  their  association  there  and  meet  once  a  month,  that  is,  the 
managers  of  these  large  terminal  elevators  meet  there  once  every 
month.  At  the  starl  we  senl  out  the  reports  to  the  Zone  Agent, 
and  then  it  appears  thai  these  managers  got  ratings  of  the  various 
elevators  which  wcr.-  posted  up  on  the  floor  of  the  Exchange. 
They  at  once  started  to  compare  their  ratings  at  this  meeting 
and  some  of  them  were  good  and  some  were  bad.  That  had 
a  tendency  to  stimulate  their  interest  in  trying  to  have  one  ele- 
vator compare  favorably  with  the  other  as  far  as  good  rating 
concerned,  We  did  not  continue  that  practice,  but  there  is 
no  question  bul  that  it  had  its  effect.    <  >nce  they  got  that  rating. 

84 


the  manager  made  it  a  point  to  impress  upon  his  superintendent 
to  keep  that  plant  in  good  shape.  As  far  as  keeping  the  plants 
clean  and  carrying  out  the  suggestions  we  made  along  those  lines, 
we  have  had  very  good  co-operation.  We  have  also  had  to 
contend  with  the  lantern  in  Minneapolis  to  some  extent,  as  you 
have  had  in  the  Eastern  district.  As  a  whole,  most  of  the 
superintendents  understand  the  hazard  of  using  a  lantern,  and 
we  have  only  two  or  three  in  that  city  who  continue  along  this 
line.  The  milling  journals  aud  trade  journals  have  given  us 
good  co-operation,  by  giving  notices,  whenever  we  desired  them, 
relative  to  meetings,  and  they  have  written  up  the  results  of  some 
of  these  larger  meetings,  such  as  Dr.  Brown  and  Mr.  Price 
have  conducted. 

Dr.  BROWN — How  about  the  receptions  you  have  received, 
Mr.  McCollam? 

Mr.  McCOLLAM — The  receptions  that  I  have  received  have 
been  all  that  could  be  desired  On  the  Pacific  Coast  there  are 
three  large  milling  companies,  and  every  one  of  them  is  progres- 
sive, and  they  all  seemed  determined  to  co-operate  with  me  as 
much  as  possible,  and  I  believe  in  the  case  of  one  of  the  com- 
panies especially,  they  carried  out  nearly  every  suggestion  that  I 
made,  and  I  believe  that  is  the  right  attitude ;  that  is,  it  reflected 
on  the  other  two  companies  as  well.  I  might  say  that  I  made 
a  good  many  personal  friends  in  the  milling  and  grain  trade. 
That  may  be  desirable  in  one  way  and  it  may  be  undesirable  in 
another  way.  It  made  it  rather  hard  to  make  rigid  inspections. 
On  the  other  hand,  they  always  seemed  glad  to  get  my  suggestions 
and  really  mean  to  carry  them  out.  I  might  say  with  respect  to 
one  large  mill  which  is  thirty  miles  from  San  Francisco,  and 
it  takes  a  day  to  make  the  inspection,  that  is.  making  the  trip 
and  making  the  inspection,  and  getting  back.  1  was  always  re- 
ceived warmly  and  treated  to  lunch  every  time  I  visited  there. 

Dr.  BAILEY — I  wish  to  note  briefly  my  opinion  on  the  situa- 
tion  in   the   Northwest      I   think   it   i-   very   difficult    for  the  men 

who   actually   are   in   the   work   to   size   up   the    situation   as   well 
as    some   of   those   outside.      My    feeling   has    been,   especially    in 
the  last  few  months,  that  this  work  is  leaving  a  profound  impi 
sion  on  the  industry  in  the    Northwest.     A   great   deal   has   been 
accomplished  in  setting  those  people  to  thinking,  and  giving  them 

definite,  concrete  Suggestions  tO  cany  out  in  the   future  in  either 

remodeling  or  rebuilding  plants  in  that  district. 

85 


Dr.  BROWN — I  am  sure  this  statement  is  very  gratifying, 
especially  from  one  who  was  at  one  time  associated  with  us, 
and  since  that  time  and  before  has  been  associated  with  the  trade. 
He  has  been  able  to  obtain  a  perspective  that  we  probably  could 
not  get.  I  would  like  to  ask  the  men  in  charge  of  the  district 
to  say  in  just  one  or  two  words  whether  they  feel  that  the  work 
has  been  better  received  in  the  past  year  than  it  was  last  year, 
or  in  the  past  few  months ;  or  what  has  been  the  receptivity  of 
the  trade;  has  it  been  increasing  or  decreasing? 

Mr.  BROWN — In  our  work,  I  will  say  "yes,"  it  has  been 
improving  during  the  last  year.  I  think  the  fact  that  the  work 
was  taken  up  in  co-operation  with  the  Grain  Corporation  has 
to  a  certain  extent  given  us  a  better  introduction  at  the  plants. 
Perhaps  the  management  has  a  very  healthy  respect  for  the 
Grain  Corporation,  or  perhaps  the  work  has  been  brought  to 
their  attention  more  forcibly  through  articles  in  magazines,  and 
they  seem  to  be  more  familiar  with  the  work  now  and  are 
more  anxious  to  obtain  our  opinion  on  the  subject. 

Mr.  BRADY — I  feel  about  the  same  as  Mr.  Brown  along 
those  lines.  There  is  no  question  but  what  they  are  paying  more 
attention  to  the  dust  hazard  than  they  have  before.  That  is 
simply  due  to  the  educational  work  that  has  been  done  along  this 
line.  As  far  as  being  received  any  better  now  than  we  have 
been  in  the  past,  we  are  getting  about  the  same  reception. 

Mr.  McCOLLAM— I  think  Mr.  Brown  has  struck  the  key- 
note of  the  matter  when  he  said  the  work  was  becoming  very 
well  known  among  the  milling  trade.  It  is  really  a  necessity, 
and  I  think  they  have  realized  that  now,  and  that  is  why  we 
have  been  received  in  such  a  hearty  manner  by  the  trade. 

Dr.  BROWN — Is  there  any  further  discussion  upon  this  side 
of  our  inspection  work?  If  not,  I  think  we  will  proceed  to  the 
general  discussion  of  experiences 

GENERAL  DISCUSSI*  >\  <  ►F   EXPERIENCES 
IX  MAKING  [NSPECTK  >NS. 

Dr.  BR(  >\\  X     1  am  sure  thai  all  of  us  who  have  been  in 
the  tu-ld,  who  have  been  in  contacl  with  the  trade,  and  par 
ticularl>    you  men  who  have  had  an  actual  contacl  with  the 
men   who  arc   working  in   the  plants,  must   have  some   ver> 
interesting  things  to  tell  us  of  your  experiences,  of  the  results 

86 


of  your  particular  work.  I  am  sure  we  would  be  very  glad 
to  have  a  general  discussion  of  this  question  from  each  and 
every  one.  Don't  hesitate  and  wait  one  upon  the  other,  but 
somebody  start.     If  you  don't  I  will  call  upon  someone. 

Mr.  HELMKAMP— I  might  say  that  at  the  start  of  the 
work  in  Buffalo,  N.  Y.,  we  started  putting  on  demonstrations 
and  visiting  each  elevator  and  in  all  my  visits  there  we  had 
very  good  meetings.  However,  when  I  got  to  the  Central 
District  this  work  had  been  very  well  covered  by  Professor 
Fitz  and  Professor  Swanson  in  the  states  of  Kansas  and 
Oklahoma  and  even  though  most  of  these  plants  had  had  a 
demonstration  put  on,  I  found  no  trouble,  except  in  possibly 
a  half  dozen  instances  where  they  did  not  desire  any  demon- 
stration. So  I  think  that  alone  shows  that  the  work  could 
be  continued  along  these  lines. 

Mr.  BODNAR — In  connection  with  the  small  blower  that 
we  have  been  using  for  giving  dust  explosion  demonstrations 
is  an  experience  that  occurred  to  me  for  the  first  time.  1  was 
giving  a  demonstration  with  corn  starch.  The  glass  tube  had 
something  like  two  inches  of  dust  in  it  and  the  resulting  ex- 
plosion from  this  amount  of  dust  was  sufficient  to  make  the 
windows  and  doors  of  the  office  in  which  the  demonstration 
was  being  given  rattle  quite  audibly.  As  nothing  like  this  had 
ever  occurred  during  a  demonstration  in  my  experience,  to 
prove  that  no  wind  from  the  outside  had  caused  the  windows 
and  doors  to  rattle,  I  immediately  recharged  the  blower  with 
a  trifle  more  dust  than  on  the  previous  occasion.  This  time 
there  was  no  doubt  about  it.  Even  the  small  amount  of  dust 
I  was  using  was  sufficient  to  develop  a  pressure  which  had  its 
effect  on  the  windows  and  doors.  The  manager  and  the  men 
around  showed  quite  a  bit  of  interest  in  the  demonstration. 
The  manager  of  the  elevator  declared  that  if  I  ever  revisited 
their  plant  I  would  certainly  find  it  cleaned  up  properly. 

Mr.  WITMER— I  feel  that  the  "baby"  elevator  and  the 
cheese  cloth  demonstrations  were  a  great  assistance  in  our 
work.  I  find  that  after  giving  demonstrations  to  the  men  at 
the  different  plants  they  were  more  careful  and  took  a  greater 
interest  in  keeping  their  plants  clean.  In  several  Instan 
which  1  recall,  the  workmen  when  not  busy  with  their  regular 
work  would  be  found  removing  dust  accumulations  from 
within  the  building,  although  having  no  instructions  to  do  so. 

87 


Mr.  PRICE — I  had  hoped  Mr.  Witmer  would  tell  us  about 
the  demonstration  in  which  he  assisted  here  in  New  York, 
using  the  ''baby  elevator." 

Mr.  WITMER — That  demonstration  was  in  a  church, 
possibly  the  accoustics  may  have  had  something  to  do  with 
it.  The  report  was  very  loud.  The  top  went  oft*  very  suc- 
cessfully and  I  believe  everybody  was  surprised  and  dumb- 
founded when  they  beheld  the  flame  shoot  out  of  the  elevator. 
We  had  quite  a  gathering — one  hundred,  possibly — and  every- 
one seemed  to  be  greatly  interested. 

Mr.  ROETHE — My  contact  with  the  officials  and  em- 
ployees of  different  mills  and  elevators  has  been  limited  to 
visits  in  connection  with  tests  made  along  static  studies  and 
for  that  reason  I  have  not  had  the  chance  to  get  around  as 
much  as  most  of  the  men,  but  I  was  particularly  impressed 
during  my  two  weeks  of  investigational  work  last  summer  by 
the  attitude  shown  by  the  different  managers  and  foremen, 
particularly  at  Seattle  and  Minneapolis.  When  we  stated 
the  nature  of  our  visit  the  managers  were  very  anxious  to 
help  us  in  every  way  possible.  They  were  interested  even  to 
the  extent  of  accompanying  us  from  floor  to  floor  to  see  what 
developed  and  were  very  anxious  to  receive  any  information 
which  would  enable  them  to  eliminate  static  charges,  and  I 
would  very  much  like  to  see  a  further  study  made  over  a  suc- 
cession of  days  during  the  winter,  perhaps,  in  order  that  con- 
clusive results  could  be  obtained  and  this  information  be 
compiled  and  published  in  an  approved  form. 

Mr.  LIND — I  can  cite  possibly  two  instances.  I  will  refer 
now  to  a  new  terminal  in  Minneapolis,  a -three  million  bushel 
plant  of  recent  construction.  I  happened  to  be  there  possibly 
two  months  ago,  and  I  was  furnished  with  a  guard  who  showed 
me  throughout  the  entire  plant  and  who  also  railed  particular 
attention  to  the  various  improvements  that  they  have  in- 
stalled with  reference  to  handling  the  dust  hazard.  Trior  to 
this  lasl  visit  I  had  also  had  a  talk  with  the  superintendent  at 
a  meeting  that  took  place  in  one  of  the  large  elevators,  an- 
other plant  close  by,  in  which  lie  said  they  were  experiencing 

considerable  difficulty  in  their  tunnels  with  reference  to  dust 
accumulation.  This  tunnel  was  two  blocks  long  ami  while 
the)  used  a  pick-up  system  on  the  return  end,  they  were  not 
able  t<>  eliminate  the  accumulation  entirely  and  for  that  reason 
would  like  to  have  im-  accompany    him  through  an  inspection 

88 


tour  of  the  tunnel,  which  I  did.  At  this  time  the  tunnel  was 
in  a  very  dusty  condition  and  I  suggested  then  a  collecting 
system,  hooded  over  the  entire  length  of  the  conveyor  belt 
at  intervals  of  possibly  40  feet,  and  he  then  suggested  that  it 
may  not  meet  with  the  approval  of  the  various  state  weigh 
masters  and  the  State  Grain  Weighers  Commission,  but  they 
were  willing  to  experiment  further  and  they  did  so.  After 
the  installation  had  been  completed  I  again  went  over  the 
plant  with  this  superintendent  and  they  had  these  suction 
hoods  installed  about  every  40  feet.  The  belt  conveyor  is  36 
inches  wide.  It  is  a  direct  suction  in  a  sense  but  indirect  in 
another  sense,  as  the  hoods  are  possibly  6  inches  or  more 
away  from  the  surface  of  the  belt.  Since  the  installation 
they  now  have  no  trouble  whatever  with  dust  accumulations 
and  you  can  see  the  entire  length  of  the  tunnel  from  the  ele- 
vator end  to  the  mill  end.  There  were  several  other  rcom- 
mendations  that  I  advised,  which  have  been  made,  among 
them  the  installation  of  vapor  proof  globes  throughout  the 
entire  tunnel. 

Dr.  BROWN — I  am  sure  that  we  greatly  appreciate  this  re- 
port and  I  might  state  in  that  connection  that  we  have  always 
had  excellent  co-operation  with  the  large  companies  in  Minne- 
apolis. To  give  you  a  little  idea  of  their  interest  in  the  dust 
question  I  might  relate  an  incident  which  occurred  in  Minne- 
apolis in  the  Fall — when  we  had  our  meeting  there  in  November. 
Mr.  Fitzimons  and  1  dropped  around  to  the  office  of  the  largest 
flour  company  and  we  found  there  one  of  the  officials  of  another 
large  flour  company.  Among  other  things,  we  were  discussing  with 
him  the  dust  question.  lie  told  me  that  they  were  considering 
an  installation  whereby  they  would  precipitate  the  dust  and 
keep  it  from  coming  out  of  their  collectors  by  use  of  a  spray, 
in  other  word-,  by  means  of  washing  the  air.  1  raised  the  ob- 
jection that  they  would  waste  that  product.  He  -aid:  "It  is  not 
a  question  of  the  1"--  and  value  of  the  dust.  It  i<  a  question 
of  preventing  dangerous  conditio] 

Mr.  REED— I  think  mi  ou  men  have  had  some  inter 

esting  experiences,  but  1  consider  that  ['ve  had  the  most  inter- 
xperience  of  any  of  you.  1  don't  think  any  of  you  have 
ever  had  two  policemen  knock  mi  your  door  a:  6  o'clock  in 
the  morning  and  hand  you  a  subpeona.  1  don't  think  any  of  you 
have  had  the  experience  of  reading  what  you  did  not  say  in  the 
morning  newspaper.     I   wish  t<»  relate  several  other  very  int 

89 


esting  experiences  that  I  have  had.  In  one  case  down  in  West 
Virginia  I  interviewed  the  general  manager  of  the  largest  mill 
in  that  section  of  the  country.  In  my  efforts  to  explain  the  work 
to  him  I  received  a  cool  reception.  He  told  me  that  he  knew 
all  about  dust  explosions  and  that  I  had  better  go  upstairs  and 
talk  to  the  miller.  He  objected  to  the  men  seeing  a  demonstra- 
tion. In  the  interview  with  the  miller  I  was  given  every  and 
all  consideration  that  could  be  given  to  me.  After  I  had  seen 
the  miller  I  walked  down  stairs  to  get  my  elevator  in  shape  and 
in  walking  through  the  mill  floor  I  noticed  this  same  general 
manager,  with  a  cigarette  in  one  hand,  strolling  through  the 
building.  In  talking  to  me,  with  a  cigarette  in  one  hand,  he 
said :  "I  read  all  your  literature  and  I  know  everything  about 
dust  explosions."  He  knew  all  about  dust  explosions  and  yet 
there  he  was  strolling  through  the  mill  with  a  lighted  cigarette. 
There  were  two  explosions  in  that  plant  and  in  one  case  the 
plant  was  destroyed  by  a  fire  from  a  dust  explosion.  The  miller 
related  two  instances  where  explosions  had  originated  in  the 
rolls. 

Another  instance  down  in  Virginia,  I  interviewed  the  head 
miller  of  a  very  large  mill  in  that  section.  I  told  him  I  wanted 
some  dust  to  blow  up  the  small  elevator.  He  said,  "I  don't  know 
of  any  place  unless  we  go  down  in  the  basement."  We  went 
<lown  into  the  basement.  The  electric  light  bulb  had  burned  out. 
"Would  it  be  safe  to  strike  a  match?"  he  asked  me,  even  after 
1  had  told  him  about  the  dangers  of  open  flames  in  mills  and 
elevators. 

Mr.  McCOLLAM — I  am  very  much  interested  in  that  spray 
method  of  collecting  dust.  That  is  a  method  used  in  chicle  re- 
fineries. They  take  that  into  solution  and  crystallize  it  out 
again.  I  had  hoped  you  would  say  something  about  electro- 
magnetic or  electrostatic  collection  of  dust. 

Dr.  BROWN — Well,  I  don't  believe  we  want  to  discuss  thai 
particular  question  righl  now.  1  might  bring  that  OUt  possibly 
in  the  paper  I  may  give  in  the  morning.    1  will  keep  that  in  mind. 

Mr.  REED— You  just  made  a  statement  that  one  concern 
considered  the  necessity  of  removing  the  dust  more  essential  than 
the  necessity  of  keeping  the  dust  and  selling  it.  In  other  words 
von  laid  more  stress  on  the  removal  of  the  dust  than  on  its  value. 
I  was  inspecting  a  feed  grinding  plant  in  Pittsburgh  last  year,  in 
which  the  manager  stated  he  wanted  all  the  dnst  he  could  get, 

for  feed,  as  lie  paid  good  money  for  it. 

90 


Dr.  BROWN — Another  pleasant  experience.  We  will  pass 
this  up  at  the  present  time  and  unless  someone  else  has  some- 
thing to  say  on  this  subject  will  pass  on  to  the  next  paper. 

Mr.  DEDRICK — I  would  like  to  relate  a  little  experience 
on  the  effect  that  the  big  explosion  at  Cedar  Rapids  had  in 
Chicago.  Shortly  after  our  work  ended  with  the  Government 
I  received  a  telephone  call  from  a  large  elevator  concern  asking 
me  to  come  over.  They  wanted  to  have  an  interview  in  regard 
to  making  some  suggestions.  They  were  very  much  alarmed 
over  the  possibility  of  having  a  dust  explosion  at  their  new 
plant — feed  plant — concrete — supposed  to  be  one  of  the  latest 
improved  plants.  So  I  went  over  and  we  had  a  little  talk  and 
they  requested  me  to  go  over  both  elevator  and  feed  plants  and 
make  certain  suggestions  to  the  superintendent  and  make  a 
written  report,  with  drawings,  suggesting  the  different  points 
where  they  might  make  improvements.  Mr.  Hibbard  and  I  spent 
half  a  day  or  more  going  over  the  plant.  Wherever  there  was 
dust  made,  as  at  the  elevator  heads,  bottom  of  the  boots,  in 
basement,  along  the  belt  conveyors,  certain  rolls  and  feeders, 
faulty  dust  collector  connections,  etc.,  we  made  a  drawing.  They 
were  having  one  difficulty  with  their  bins  which  were  made  of 
steel  and  rather  narrow.  The  material  packed  in  the  hopper 
outlet  so  that  when  they  came  to  draw  it  out  it  would  bank  up 
in  the  hopper.  They  had  to  make  holes  at  the  junction  of  the 
spouts  and  hopper  so  that  they  could  use  a  pole  to  poke  and 
start  the  stuff.  I  suggested  the  plan  of  putting  an  agitator  in 
the  bins  with  arms  extending  out  so  that  they  could  work  it 
from  below,  so  that  this  would  start  the  stuff  without  having  it 
come  down  with  a  rush  and  causing  a  great  litter  and  clouds  of 
dust.  There  were,  I  think,  altogether,  about  15  different  points 
where  they  could  make  improvements,  and  I  made  drawings 
showing  how  these  could  be  accomplished.  When  I  submitted 
the  report  they  assured  me  they  were  going  to  follow  these  out. 
I  don't  know  whether  they  did  or  not,  as  1  was  never  there  again. 
I  left  the  work  shortly  after  that.  Perhaps  Mr.  Ilibbard  would 
know. 

Mr.  HIBBARD— I  was  at  the  plant  about  three  months 
and  they  were  still  "going  to  follow  out  those  recommendation 

REVIEW  I  >F   EXPD  >SH  >NS   DURING    PAST   VE  \K 
I  )r.  BR(  >WN     We  have  next  on  the  program  a  review  of  the 

various   explosions    which    have   occurred    during   the    past    year 

91 


As  there  arc  several  of  these  and  our  afternoon  is  somewhat 
crowded  and  we  are  planning-  to  have  a  little  talk  from  Mr. 
Barnes,  from  Dr.  Alsberg  and  possibly  from  some  other  men  re- 
garding some  other  phases  of  the  work,  I  feel  that  we  should 
limit  the  papers  and  discussion  on  these  subjects  to  not  over  ten 
minutes  each  and  consequently  I  am  going  to  call  you  at  the  end 
of  five  minutes.  This  will  give  you  one  minute  to  sum  up  and  4 
minutes  for  discussion.  The  first  paper  will  be  by  Mr.  Reed  on 
the  Kansas  City  explosion.  Before  we  have  the  discussion  I 
will  then  call  upon  Mr.  Helmkamp  and  we  will  have  the  general 
discussion  of  the  two. 

KANSAS  CITY  EXPLOSION 

By  Mr.  J.  O.  Reed. 

The  Murray  elevator  at  Kansas  City,  Mo.,  was  destroyed  by 
a  dust  explosion  on  September  13,  1919.  Fourteen  men  were 
killed,  ten  injured,  and  the  property  loss  was  estimated  at 
$650,000.  The  plant  was  constructed  entirely  of  concrete,  tile, 
and  steel,  and  the  most  modern  type  of  machinery  obtainable 
was  used.  The  Murray  elevator  was  a  plant  of  one  and  one  half 
million  bushels  capacity,  and  consisted  of  three  units,  the  working 
house  and  the  two  units  of  storage  tanks.  The  explosion,  accord- 
ing to  the  result  of  the  investigations  that  were  conducted  after 
the  explosion  occurred,  originated  in  the  basement.  Now  this 
basement  was  perfectly  tight.  The  walls  in  the  working  floor 
were  tight  and  for  that  reason  the  working  floor  walls  and  the 
floor  of  the  working  floor  were  blown  out.  The  explosion  propa- 
gated up  through  the  manlift  tower  on  the  side  of  the  elevator  into 
the  "Texas"  and  blew  out  the  tile  walls  of  the  "Texas".  I  don't 
think  there  is  an  explosion  which  has  ever  occurred  in  a  grain 
elevator  in  this  country  in  which  there  was  more  force  displayed. 
F  doubt  if  the  Cedar  Rapids  explosion  displayed  any  more  force. 
The  story  of  the  explosion  will  probably  be  of  interest  to  some 
of  you.  The  men  in  the  plant  were  cleaning  up  and  during  the 
course  of  the  cleaning-up  process  the  explosion  occurred.  Of 
course  the  newspaper  reports  came  out  later  on  and  made  the 
Statemenl  that  there  was  so  much  dust  stirred  up  in  the  sweeping 
SS  of  the  plant  that  a  spontaneous  combustion  of  dust  took 
place  and  an  explosion  naturally  would  result.  I  would  like  to 
give  vmi  just  a  few  points  in  the  recommendations  that  we  made. 
The  firsl  inspection  was  made  on  the  5th  of  September,  1919.  In 
this  inspection  t lie   following  notations  were  made  regarding  the 


condition  of  the  plant,  for  instance,  the  equipment  was  said  to  be 
good  and  the  maintenance  very  poor.  These  are  the  direct  state- 
ments which  were  made  in  the  report :  "Clean  up  this  house  and 
keep  it  clean.  Employ  sweepers.  Install  vapor  proof  globes  and 
remove  all  carbon  filaments."  At  the  end  of  the  report  the  state- 
ment was  made :  "This  plant  is  dangerous  and  even  though  fire- 
proof, will  explode  if  its  present  condition  is  permitted  to  exist." 
That  statement  was  made  on  the  fifth  day  of  September.  On  the 
12th  of  September  another  inspection  was  made  and  the  state- 
ment was  made  in  the  report  that  the  maintenance  of  the  plant 
was  still  poor  and  that  the  first  recommendations  should  be  carried 
out.  Now  I  would  like  to  give  you,  or  just  state  to  you  the  con- 
dition of  that  plant  the  day  before  the  explosion  occurred — but 
I  haven't  time.  The  Coroner's  record  contains  all  the  evidence  if 
you  are  interested. 

Dr.  BROWN— Mr.  Helmkamp  will  give  us  a  little  of  the  effect 
of  the  explosion  on  the  inspection  work  in  the  vicinity  of  Kansas 
City. 

THE  EFFECT  OF  THE  KANSAS  CITY  EXPLOSION  (  IN 
INSPECTION  WORK  IN  THE   SOUTHWEST 

By  H.  J.  Helm  k amp. 

It  was  not  until  one  month  after  the  explosion  at  the  Murray 
elevator  in  Kansas  City  that  1  took  up  the  inspection  work  in  that 
vicinity.  ( )rie  of  my  first  visits  was  to  the  officers  and  the  man- 
agement of  the  Murray  Grain  Elevator.  My  reception  there  was 
all  that  could  be  expected.  All  the  recommendations  which  were 
offered  by  our  force  were  gladly  received  and  I  am  pleased  to 
say  that  a  great  number  of  them  are  being  carried  out  in  re- 
constructing their  plant. 

During  my  inspections  of  plants  in  the  Southwest  For  the  first 
few  months  the  subject  of  the  Mnrra\  explosion  was  brought  up 
a  great  many  time-.    Of  course  when  there  was  any  misunder- 
standing at  any  time  as  to  the  cause  1  corrected  them  and  I 
plained  the  cause  of  the  disaster  to  the  best  of  my  ability. 

The  terminal  elevators  in  Omaha  and  Kansas  City,  with  the 
possible  exception  of  one  or  two,  I  found  to  be  the  cleanest  that 
I  have  ever  found  in  any  one  locality  and  1  think  that  this  is  the 
one  big  improvement  which  can  be  said  to  result  from  the  Kansas 
City  explosion.     In  nearly  all  ca  immendations  were  \ 

gladly  received  and  in  many  ca»  I  was  asked  to  pay  particular 
attention  to  certain  parts  of  the  plant  or  to  certain  equipment  in 


the  plant  in  order  to  determine  the  dust  explosion  hazard.  At  all 
times  every  possible  courtesy  was  shown  to  the  men  engaged  in 
this  work. 

Another  improvement  resulting  directly  from  the  Murray 
explosion  was  hiring  of  regular  sweepers  by  all  the  plants  that  had 
heretofore  had  none,  while  those  having  sweepers  put  on  addi- 
tional men  in  order  to  keep  the  plant  in  as  good  a  condition  as 
possible.  . 

The  explosion  brought  forth  renewed  activity  on  the  part  of 
the  fire  underwriters  and  insurance  men.  These  men,  who  in  the 
past  had  regarded  a  fire-proof  plant  as  an  extremely  safe  hazard, 
now  began  to  hustle  about  and  reinspect  the  plant  with  the  dust 
explosion  hazard  in  view.  Several  times  during  my  inspections  I 
encountered  these  men  and  together  we  inspected  the  plant  and 
discussed  the  various  hazards,  So  as  another  result,  I  might  say 
that  the  Kansas  City  explosion  brought  home  forcibly  to  the 
insurance  and  fire  underwriters  the  dangers  of  dust  explosions, 
and  the  fact  that  a  fire-proof  plant  was  not  explosion-proof. 

In  summary  I  will  say  that  the  effect  of  the  explosion  on  in- 
spection work  in  the  Southwest  was  not  only  to  make  the  in- 
spection work  easier  because  of  the  fact  that  the  superintendent 
made  it  a  point  not  to  hide  any  of  the  dangerous  places,  but 
would  point  them  out  and  inquire  for  the  remedy ;  but  also  the 
fact  that  recommendations  were  gladly  received,  although  in  some 
instances  they  were  not  followed  out  as  promptly  as  you  would 
judge.  However,  in  many  cases  the  plants  which  had  been  rated 
as  in  C  condition  by  Mr.  Reed  were  found  to  be  in  A  condition 
upon  my  next  inspection. 

Dr.  BROWN— Mr.  Helmkamp  has  not  used  all  of  his  time. 
Mr.  Reed  may  utilize  the  one  and  one-half  minutes  remaining 
to  tell  us  about  the  condition  of  that  plant. 

Mr.  REED — The  elevator  was  found  to  be  in  a  bad  condi- 
tion. Only  the  floors  had  been  swept  up,  where  there  was  an 
Indication  of  sweeping.  Everywhere  there  were  dust  accumula- 
tions overhead  and  no  effort  had  been  made  to  remove  these 
accumulations.  At  places  there  was  so  much  dust  on  the  flange 
of  the  "1"  beams  that  no  more  dust  could  accumulate  there,  be- 
cause the  angle  of  repose  had  been  reached.  Every  here  and 
there  were  piles  of  dust.  Tn  the  hasement  there  was  very  much 
•  hist,  especially  overhead  and  on  the  tnmking  of  the  dust  collect- 
ing system  used  for  collecting  the  sweepings.  This  dust  on  the 
trunking  of  the  dust  collecting  system  was  very  black,  old,  fine 

94 


and  dry.    I  gathered  this  dust,  with  the  help  of  one  of  the  Grain 
Corporation  men,  in  a  portion  of  a  burlap  sack  and  secured  all 
I  desired  within  about  one  lineal  foot  on  the  pipe.    There  was  an 
excessive  amount  of  dust  in  the  shaft  containing  the  stairways, 
elevator  lift,  and  main  rope  drive.     There  were  piles  of  dust  and 
growing   grain   in   the   tunnels   leading   underneath   the    storage 
tanks.     The  dust  was  several   inches  thick  on  and  underneath 
two  grain  cleaning  machines  located  in  the  northern  end  of  the 
working  floor.    The  switch  and  fuse  boxes  were  still  very  dusty. 
There  was  an  excessive  amount  of  dust  and  oil  on  the  journals. 
There  was  a  hot  bearing  on  the  countershaft  driving  the  fan  on 
the  top  floor  with  a  great  amount  of  oil  on  the  journal.     Oil,  it 
appeared,  had  run  through  the  top  floor  from  the  blower   fan, 
and  a  large  pan  had  been  placed  underneath  this  floor  to  catch 
the  oil.     On  the  top  floor  I  found  a  very  poor  extension  cord 
worn  at  the  socket.    There  were  many  carbon  filaments  used  for 
lighting  everywhere  in  the  plant.     There  was  no  protection  on 
electric  light  bulbs  and  almost  all  these  bulbs  were  very,  very 
dusty.     No  vapor  proof  bulbs  were  used  in  the  plant.     I  tried 
to  inspect  several  elevator  boots,  but  was  unable  to  pull  the  slide 
out   from  underneath  the  revolving  buckets,  so  I  do  not  know 
whether  these  boots  were  clean  or  not.     The  trunkings  of  the 
dust  collecting  system  were  in  a  very  bad  condition  and  needed 
repair.     On   the  top  floor  there   was  a  partially  filled  fire   ex- 
tinguisher.     Replacements,    such    as    belting,    elevator    buckets, 
ropes,  sacking,  etc.,  were  piled  everywhere  on  the  working  floor 
and  were  covered  with  dust.    The  superintendent  stated  that  the 
fan  on  the  dust  collecting  system  had  broken  down  before  my 
first  visit  and  that  it  was  for  this  reason  that  the  plant  was  dirty, 
but  I  observed  on  both  my  visits  that  the  fan  was  in  operation. 
There  was  a  great  accumulation  of  dust  under  a  large  machine 
in  the  basement.     Workmen  had  swept  around  but  not  underneath 
this  machine.     The  general  condition  of  the  elevator,  as  com- 
pared with  other  modern  elevators  of  the  same  type  that  operate 
at   full  capacity  daily,  was  dirty  and  dusty.     Without  doubt  the 
Murray   Elevator  was  tin-  poorest  kept  and  dirtiest  elevator  in 
Kansas  City. 

Dr.   BROWN     Now  you  have  the  report  of  this  explosion 

and  its  effects  on  the  plants  in  that  vicinity  before  you. 

Mr.    BAILEY      I    note    from  the  photographs  that   apparently 

tin-  grain  drier  was  completely  demolished.    Was  tl  illy 

din 

95 


Mr.  REED — That  was  demolished,  I  think,  due  to  the  fact 
that  the  walls  in  the  working  house  were  blown  out. 

Dr.  BAILEY— Well,  you  don't  think  then,  that  it  was  the 
result  of  an  explosion  within  the  drier? 

Mr.  REED— No  sir. 

Dr.  BAILEY — Grain  driers  usually  are  especially  hazardous 
since  the  dust  there  is  thick  and  dry. 

Mr.  RILEY — If  the  explosion  had  taken  place  in  the  drier 
the  elevator  wall  would  have  been  blown  in,  would  it  not? 

Dr.  BAILEY — I  was  not  assuming  that  the  explosion  origi- 
nated in  the  drier,  but  that  it  might  have  propagated  through  the 
drier. 

Mr.  PRICE — The  tremendous  force  exerted  by  the  explosion 
is  indicated  by  the  fact  that  parts  of  the  16-inch  concrete  wall 
were  found  a  considerable  distance  from  the  elevator,  so  any 
equipment  or  mechanical  devices  were  subject  to  a  great  deal  of 
force  by  something  falling  as  the  explosion  occurred. 

Mr.  REED — The  entire  working  shed  of  the  plant  was  blown 
away.  There  was  nothing  left  of  it.  I  wish  I  had  better  photo- 
graphs here.  I  would  like  to  show  you  just  how  the  drier  house 
was  blown  out.  There  is  no  indication  that  the  explosion  oc- 
curred in  it,  as  part  of  the  drier  house  would  then  probably  have 
been  on  the  working  floor. 

Dr.  BROWN — You  mean  that  the  indication  would  be  that 
it  propagated  from  the  working  house  through  the  drier? 

Mr.  PRICE — I  would  like  to  suggest,  in  connection  with  this 
explosion  at  Kansas  City,  that  the  superintendent  was  in  charge 
15  years  as  I  recall  it,  and  never  had  any  previous  experiences 
of  this  nature  and  was  recognized  as  being  very  competent.  I 
have  had  the  question  asked  a  number  of  times:  "What  reason 
can  you  g'wa  why  this  explosion  did  not  occur  before?"  Now  I 
know  how  we  feel  about  that,  but  that  to  me  is  one  of  the  peculiar 
things  about  these  dust  explosions,  and  why  it  would  occur  in 
the  Murray  Elevator  in  Kansas  City  and  not  in  any  others. 

Dr.  BR<  >WN  1  might  state-  that  here  is  a  copy  of  Mr.  Reed's 
inspection  report.  The  first  inspection  was  on  the  fifth  of 
September.  It  states:  "Tin's  plant  is  dangerous  and  even  though 
fireproof    will    explode    if    the    present    condition    is   permitted    to 

96 


exist."     This  statement  was  made  on  the  fifth  and  repeated  on 
the  twelfth. 

Mr.  REED — Saturday  afternoon  at  one  o'clock  I  wrote  a  let- 
ter to  Mr.  Fitzimons  and  descrihed  to  him  certain  things  I  had 
noticed  regarding  the  condition  of  that  plant.  I  don't  think 
I  had  more  than  mailed  the  letter  before  the  explosion  occurred. 

Dr.  BROWN — We  appreciate  having  Mr.  Barnes  with  us 
and  I  am  going  to  ask  if  Mr.  Price  will  express  to  Mr.  Barnes 
for  us  our  appreciation  of  his  activity  in  this  work  and  then 
call  on  Mr.  Barnes  for  a  few  remarks. 

Mr.  PRICE — Early  in  1917,  shortly  after  we  entered  the  war, 
Dr.  Alsberg  of  our  Bureau  felt  that  we  might  be  in  a  position  to 
assist  the  Food  Administration  in  some  manner  since  our  men 
were  familiar  to  a  large  degree  with  the  dust  explosion  hazard. 
He  suggested  at  that  time  that  we  might  get  in  touch  with  Dr. 
Raymond  Pearl,  who  was  connected  with  the  Food  Administra- 
tion. About  that  time  the  explosion  occurred  in  the  Dow  Stores 
elevator  in  New  York  City.  As  you  know,  it  was  estimated 
that  the  grain  destroyed  was  sufficient  to  provide  bread  rations 
for  an  army  of  200,000  soldiers  for  an  entire  year.  Dr.  Alsberg 
thought  that  we  should  do  something  in  the  way  of  an  emerg- 
ency campaign.  We  again  took  the  matter  up  with  Dr.  Pearl 
and  he  told  us  that  we  should  by  all  means  see  Mr.  Barnes  and 
Mr.  Bell.  We  arranged  a  conference  with  both  of  these  gentle- 
men and  they  received  us  very  kindly.  Mr.  Barnes  was  then 
arranging  a  meeting  of  the  zone  agents  in  New  York  and  re- 
quested that  we  tell  them  about  our  work.  That  started  the  co- 
operation. It  allowed  us  to  work  with  the  Grain  Corporation. 
Our  pledge  cards  were  issued  that  you  have  been  using  and  also 
a  number  of  copies  of  the  circular  and  poster  in  our  emergency 
campaign.  This  continued  up  to  the  fust  of  July,  I'M'',  at  which 
time  the  emergency  appropriation  was  discontinued.  At  that 
time  the  Grain  Corporation  sent  Dr.  Duval  to  the  Chicago  Con- 
ference and  through  his  interesl  we  arranged  with  Mr.  Ban 
for  the  Grain  Corporation  to  continue  this  work.  I  know  we  all 
feel  and  appreciate  what  Mr.  Barnes  has  done  lot  us,  because 

the   cooperation    has   been    most    pleasant    and   the    work    well 
ceived.     We  are  more  than  glad  to  have  him  with  US  today  and 
I  take-  pleasure  in  presenting  Mr.  Barnes.     (Applaus< 


"7 


STATEMENT  BY  MR.  JULIUS  H.  BARNES,  PRESIDENT, 
U.    S.   GRAIN   CORPORATION. 

I  have  a  great  respect  for  the  trained  mind.  I  conceive  that 
the  most  useful  purpose  that  a  mere  business  man  can  serve  is 
to  make  effective  the  suggestions  of  trained  observation.  Rarely 
has  a  man  been  engaged  in  a  work  in  which  the  direct  result  is 
so  apparent  as  it  is  in  this  work.  Wherever  the  tale  of  the  show- 
ing of  the  grain  dust  explosion  prevention  work  from  August, 
1917,  to  May,  1919,  is  told  it  makes  a  marvelous  impression  that 
carries  conviction.  If  we  take  any  credit  for  cooperation  and 
association  in  it,  it  is  because  we  had  vision  enough  to  see  its  im- 
portance. We  get  a  complete  and  lasting  satisfaction  out  of  the 
results  of  it.  I  have  a  picture  of  you  men  as  faithfully  in- 
terpreting the  details  that  to  the  average  man  would  appear  un- 
important— I  have  a  picture  of  you  as  faithfully  interested  that 
the  proper  precautions  might  be  taken  and  the  result  comes  be- 
fore us  in  the  splendid  results  achieved.  I  am  really  approach- 
ing the  close  of  this  service  and  your  work  under  our  encourage- 
ment with  considerable  regret.  I  regret  it  because  I  am  afraid 
that  in  our  commercial  structure  the  vision  will  not  be  broad 
enough  to  carry  it  on  in  the  way  in  which  it  should  be  carried  on. 
I  look  to  the  intelligence  and  foresight  of  the  big  business  or- 
ganizations rather  than  yet  to  a  real  appreciation  on  the  part  of 
the  Government,  which  represents  the  general  public,  to  see  the 
picture  as  we  see  it.  I  believe  that  you  have  made  a  record  that 
you  should  be  proud  of.  I  desire  to  thank  you  for  the  spirit  with 
which  the  work  has  been  carried  on  and  the  efficiency  with  which 
it  has  been  done.     (Applause.) 

Mr.  PRICE — We  are  also  pleased  to  have  with  us  at  this 
conference  the  Chief  of  the  Bureau  of  Chemistry  from  Wash- 
ington, who  has  been  directing  the  work  there  while  the  Grain 
Corporation  has  been  handling  the  work  here.  We  shall  be 
pleased  to  hear  from  Dr.  Alsbi 

STATEMENT  BY  DR.  C.  L.  ALSBERG,  CHIEF,  BUREAU 
(  >F  CHEMISTRY,  U.S.  DEPT.  OF  AGRICULTURE 

Every  man,  of  course,  who  amounts  to  anything  at  all,  has 
some  very  personal  ideals  of  service.  My  own  personal  ideal  ol 
service  so  far  as  the  Bureau  of  Chemistry  is  concerned  is  that 
ervice  which  the  Bureau  of  Chemistry  should  render  to  the 
people  of  the  United  States  is  that  it  should  be  the  technological 
bureau  of  the  Department   of  Agriculture — that  bureau  which 

98 


carries  on  constructive  work  and  constructive  investigations  that 
have  to  do  with  the  industries  that  use  as  their  raw  materials  the 
products  of  agriculture.  Of  course,  of  these  industries  the 
main  one  is  the  food  industry.  We,  in  the  Department  of  Agri- 
culture, are  all  apt  to  think  that  the  object  of  agriculture  is  merely 
to  furnish  the  farmer  wealth.  The  object,  however,  is  primarilv 
to  feed  the  people  and  secondarily  to  furnish  the  farmer  with 
the  best  possible  living.  Now,  in  the  Department,  we  have  been 
thinking  too  much  and  too  entirely  of  production  and  not  enough 
about  the  industries  that  use  agricultural  products  as  their  raw 
materials.  It  is  one  thing  to  increase  production.  It  is  another 
and  equally  important  thing  to  utilize  what  has  been  produced  to 
the  best  advantage.  That  is  where  my  plans,  my  hopes  for  the 
Bureau  of  Chemistry  come  in — that  it  may  be  developed  and  may 
develop  into  the  technological  bureau  of  the  Department  of 
Agriculture,  which  will  concern  itself,  as  I  have  just  said,  with  the 
development  of  constructive  work,  research  if  you  will,  develop- 
ment work  if  you  will,  involving  the  application  of  scientific  re- 
search to  the  industries  that  draw  their  raw  materials  from 
agriculture,  of  which  the  food  industry  is,  of  course,  the  most 
important.  Since  that  is  my  hope  for  the  Bureau  of  Chemistry, 
it  was  a  very  great  comfort  to  me  that  the  Grain  Corporation  and 
Mr.  Barnes  in  particular  exhibited  the  very  fine  attitude  that, 
when  it  was  not  possible  for  the  Bureau  of  Chemistry  any  longer 
to  carry  on  the  grain  dust  work,  the  Grain  Corporation  was  will- 
ing to  take  it  over  and  carry  it  through  for  another  year.  I  can- 
not say,  Mr.  Barnes,  how  much  I  personally  appreciate  your 
vision  and  your  expression  of  confidence  in  the  staff  of  men  that 
had  been  gathered  together  when  you  were  willing  to  undertake 
the  further  conduct  of  the  work.  I  can  also  say  at  the  present 
moment  that  the  disintegration  of  the  organization  which  hag 
been  built  up,  the  cessation  of  the  greater  part  of  the  work,  comes 
to  me  as  a  real  and  personal  blow,  because,  1  believe,  it  has  set 
back  the  Bureau  of  Chemistry  a  great  many  years  in  the  fulfill- 
ment of  that  development  which  we  have  marked  out  for  our- 
selves and  which  we  hope  to  attain.  This  particular  piece  of  work 
is,  1  think,  perhaps  I  should  say  undoubtedly,  the  most  splendidly 
successful  piece  of  work  along  the  1  ©operation  with  the 

industries,  along  lines  of  developing  constructive  work  with  the 
industries,  that  the  Bureau  of  Chemistry  has  ever  undertaken. 

There  have  been  many  other  pieces  of  work  during  the  lasl   five 

and  there  arc  a  good  many  pieces  ^\  work  going  on 
at  the  present  time  along  lines  of  cooperation  with  the  industri 


of  improving  conditions  in  the  industries,  of  applying  results  of 
arch  work  to  the  methods  of  improving  production  and  ser- 
vice, but  there  is  not  one,  even  of  those  which  have  been  success- 
ful, which  is  of  the  importance  of  this  particular  piece  of  work. 
Therefore,  I  say  the  breaking  up  of  this  piece  of  work  sets  back 
the  work  I  have  marked  out  for  the  Bureau  a  great  many  years. 
However,  we  are  not  going  to  give  the  work  up  entirely.  We  al- 
ways have  a  little  money  that  we  can  squeeze  out  here  or  there,  but 
about  the  best  that  we  can  hope  during  the  next  year  is  to  keep 
the  work  alive  and  do  some  of  the  fundamental  research  that  has 
to  be  done  in  collection  with  it,  so  that  if  we  are  ever  able  to  take 
it  up  again  wre  will  not  have  marked  time. 

All  I  can  say  in  conclusion  is  that  I  personally  (and  I  know 
I  can  also  speak  for  the  Secretary  of  Agriculture)  fully  appre- 
ciate and  value  the  work  which  you  gentlemen  have  done,  the 
work  which  the  Grain  Corporation  has  done,  that  I  personally 
want  to  thank  each  one  of  you  for  the  loyal  work  that  was  done 
first  when  you  were  members  of  the  Bureau  of  Chemistry  and 
later  when  you  were  members  of  the  Grain  Corporation.  I  wish 
also,  Mr.  Barnes,  to  thank  the  Grain  Corporation  for  enabling 
us  to  at  least  carry  on  the  work  a  year  longer  than  would  otherwise 
have  been  possible.     (Applause). 

Mr.  PRICE — I  understand  Mr.  Barnes  has  never  seen  our 
elevator  blow  up. 

Dr.  ALSBERG — (preparing  to  leave).  If  there  is  any  way 
in  which  the  Bureau  or  I  personally  (that  is  all  you  who  are  not 
going  to  stay  with  us)  can  help  you  now  or  in  the  future  why 
just  say  so. 

PORT  COLBORNE  EXPLOSION. 

Dr.  II.  II .  Brown. 

(  >ne  Sunday  afternoon  down  in  Washington,  my  attention 
was  called  to  a  little  clipping  in  a  newspaper  about  an  explosion 
in  Port  Colborne,  Ontario,  where  a  number  of  men  were  killed. 
extensive  property  damaged,  etc.  I  tried  to  get  a  little  further 
information  from  the  pros  and  then  decided  that  somebody 
should  go  Up  there.  I  left  that  evening  and  was  on  the  ground 
the   next    morning.      1    found   the-   plant    had   been   almost    totally 

destroyed.  I  mighl  slate  that  it  was  a  vn\  interesting  investi- 
gation because  there  were  SO  many  different  leads  which  would 
indicate  different  possible  Causes.  The  Mrsl  that  was  considered 
by    most    men    was   that    a    motor   had    Started    the   explosion   due 

KM) 


to  hot  bearings.  This  was  because  of  the  fact  that  there  was  dust 
accumulated  on  it  and  there  had  been  a  little  fire  around  it 
before  luncheon.  But  that  idea  had  to  be  discarded  when  we 
considered  that  the  plant  was  not  in  operation  at  the  time  of  the 
explosion.  Inasmuch  as  the  plant  had  closed  down  there  could 
have  been  no  dust  in  suspension  at  that  point.  When  we  went 
down  into  the  basement,  we  found  a  conveyor  belt,  running 
from  one  of  the  boots,  badly  burned  and  a  number  of  men  were 
sure  that  that  was  the  cause  of  the  explosion.  Then  right  close 
to  it  there  was  another  conveyor  belt  badly  choked,  grain  thrown 
out  over  the  floor,  and  that  looked  sort  of  bad,  but  they  thought 
that  that  might  easily  have  happened  when  the  belt  dropped,  as 
both  of  these  belts  had  dropped.  We  went  up  to  the  next  floor 
and  we  found  on  the  floor  beside  this  one  that  had  dropped  a  pile 
of  grain  and  the  buckets  which  had  dropped  down  there.  That 
might  have  happened  after  the  explosion.  We  started  along 
upstairs  and  found  that  all  of  the  elevator  legs  had  been  blown 
out,  some  worse  than  others.  The  bin  floor  was  covered  over 
and  a  number  of  the  walls  had  been  blown  out.  After  sifting 
all  the  evidence  available  and  taking  the  opinions  of  a  number 
of  different  men  and  trying  to  deduct  the  facts  from  the  opinions 
and  from  the  evidence,  I  might  state  that  contrary  to  the  opinions 
of  the  majority  of  the  men  with  whom  I  talked  the  circum- 
stantial evidence  was  so  conclusive  that  I  could  not  agree  with 
the  majority  of  them  because  of  the  fact,  for  instance,  that  the 
pile  of  grain  which  was  in  front  of  the  lofter  leg  which  had 
opened  and  where  the  buckets  were  hanging  down — that  that 
grain  was  covered  with  material  from  above.  If  that  belt  had 
burned  in  two  and  dropped  as  a  result  of  the  explosion  this 
material  would  have  been  covered  with  the  grain.  This  indi- 
cated definitely  that  that  belt  dropped  and  the  grain  was  on 
the  floor  before  the  explosion.  There  was  no  question,  after 
a  little  further  investigation,  but  that  a  choke  had  occurred  in 
an  elevator  leg  at  ten  minutes  to  twelve.  The  men  left  the  plant 
shortly  after  and  on  their  return  at  noon  smelled  the  odor  of 
burning  rubber  which  they  thought  was  due  to  a  hot  belt  in 
the  basement — a  belt  which  had  become  hot  and  was  rubbing 
to  one  side.  The  evidence  led  conclusively  to  the  fact  that  there 
had  been  a  choke.  We  finally  found  a  man  who  had  been  to 
the  toj)  floor  of  tin-  elevator  and  only  about  two  minutes  before 
the  explosion  saw  smoke  coming  out  of  the  elevator  and  -.aw 
the  flames  of  the  burning  belt,  and  only  had  time  to  get  to 
the  first  floor  before  the  explosion. 

101 


There  are  two  interesting  facts  that  I  want  to  bring  out. 
The  side-wall  construction  of  the  bins,  trough-plate  construc- 
tion, so-called,  so  as  to  support  everything  perpendicularly  instead 
of  getting  the  side  pressure,  allowed  for  a  heavy  accumulation 
of  dust.  A  distance  from  the  top  of  the  bin  to  the  bin  floor 
of  about  six  feet  allowed  the  explosion  to  pass  through  into  the 
other  bins,  blow  through  the  bin  floor  and  the  roof 
above.  One  reason  I  believe  that  the  explosion  propagated  through 
the  bins  or  got  into  the  bins  in  the  first  place,  is  that  there  was 
an  opening  eight  inches  wide  by  the  width  of  the  elevator  belt, 
about  thirty-two  inches. 

Another  interesting  fact  which  you  may  see  from  one  or 
two  of  these  pictures  showing  the  lower  portion  of  the  plant  is 
that  there  was  not  an  explosion  in  the  basement — no  great  pres- 
sure developed  in  the  basement.  There  was  suction  there.  All 
of  the  windows  were  drawn  in.  Broken  glass  was  strewn  over 
the  floor  showing  that  the  explosion  went  upwards  over  toward 
the  working  side  of  the  house.  The  windows  in  the  basement 
were  drawn  in.  You  can  see  from  this  how  the  explosion  might 
easily  have  propagated  from  the  well  and  throughout  the  bins. 

Dr.  BROWN — Is  there  any  discussion  in  regard  to  this 
explosion? 

Mr.  RILEY — Was  the  condition  shown  in  that  picture 
due  to  fire? 

Dr.  BROWN— That  was  due  to  the  burning  of  the  belt. 
Of  course  it  burned  entirely  in  two.  When  some  of  the  men 
first  entered  the  plant  following  the  explosion  (there  was  no 
general  fire,  the  men  entered  the  plant  less  than  a  half  hour 
later)  that  particular  leg  was  red  from  fire  and  was  the  only 
one  of  the  14  in  which  there  was  fire  appearing  at  that  time, 
although  fire  later  developed  in  one  of  the  others. 

Mr.  BATES— The  only  burnable  thing  in  there  was  the 
belts  and  grain. 

Dr.   BAILE'Y     Was  this  elevator  operated  in  connection 

with  one  of  the  mills  or  in  connection  with  a  railroad? 

Dr.  BROWN — No,  it  was  not.  It  had  railroad  facilities 
but  wa-  operated  by  the  Government.  It  principally  was  a 
house  designed  to  take  in  -rain  from  boats.  Grain  was  trans- 
ferred through  the  house  to  barges  to  pass  through  the  Wetl- 
and ( 'anal. 

102 


Mr.  BATES — What  is  this  wrecked  barge  which  shows  in 
one  of  the  pictures? 

Dr.  BROWN— I  might  state  that  there  were  10  men  killed 
by  this  explosion — 4  within  the  plant  and  6  on  a  barge  which 
was  loading  at  that  time  alongside  the  plant.  I  said  the  house 
was  not  in  operation.  There  was  a  little  grain  running  from 
the  hoppers  into  the  spout — just  finishing  up  the  loading  of 
the  barge.  The  barge  was  sunk  and  the  men  killed  by  falling 
debris. 

Mr.  LIND — In  taking  up  the  reconstruction  of  this  plant, 
have  they  given  any  attention  to  means  of  eliminating  this 
hazard  ? 

Dr.  BROWN — It  is  my  understanding  that  they  are  going 
to  put  in  single  leg  elevators  from  top  to  bottom,  enclosing  the 
leg,  getting  rid  of  that  well  with  its  inherent  hazard  due  par- 
ticularly to  the  trough  plate  construction  and  the  allowing  of 
so  much  dust  to  accumulate;  also  put  the  bin  floor  down  onto 
the  top  of  the  bins.  In  reality  what  they  are  planning  to  do  is 
to  extend  the  bins  with  smooth  steel  plates  to  the  point  where 
the  original  bin  floor  was.  This  will  make  the  bins  of  tight 
construction  and  then  vents  will  be  placed  around,  which  will 
be  open  to  the  outside  air.  They  had  a  dust  collecting  system 
but  it  was  not  in  operation  on  account  of  the  activity  of  the 
Canadian  Grain  Commission. 

Mr.  LIND — Prohibiting  its  use? 

Dr.  BROWN  Prohibiting  its  use  before  the  ^rain  was 
weighed. 

Mr.  BATES— Was  the  elevator  a  total  wreck? 

Dr.  BROWN — The  bins  were  practically  intact.  The  bins 
were  not  hurt  materially  by  the  explosion  in  ni  5,     The 

explosion  seemed  to  be  largely  above  the  walls  in  the  bins 
and  of  course  went  upward,  venting  itself  at  the  top.  The 
little  building  shown  in  the  picture  is  the  office  building, 
which  was  demolished  by  the  force  of  material  blown  there. 

Mr.   BATES     -Was  the  grain  in  the  bins  burn. 

Dr.  BR<  »\\  \  Only  slight^  on  top.  The  loss  was  only 
about  five  thousand  bushels  out  of  450,000. 

Dr.    r.AIU.Y     Was    the    elevatoi  yed    in    such    a 

manner  that  the  grain  in  the  bins  could  be  remov< 


Dr.  BROWN — Not  by  normal  processes.  It  was  removed 
by  reversing  the  belts  and  allowing  the  grain  to  drop  down 
and  run  up  into  the  cars.  If  there  is  no  more  discussion  we 
will  take  up  the  Denver  explosion. 

DENVER,  COLORADO— EXPLOSION 
By  D.  J.  Price. 

The  explosion  occurred  on  January  22,  1920,  and  was  reported 
to  the  Bureau  by  the  Denver  Station  of  the  Bureau  of  Chemistry. 
We  requested  the  men  at  the  Denver  Laboratory  to  investigate 
and  ascertain  whether  or  not  there  had  actually  been  an  explosion. 
Mr.  llelmkamp,  of  our  own  force,  was  the  nearest  man  to  Denver, 
but  on  account  of  his  illness  we  were  not  able  to  get  anybody  out 
there.  The  men  at  the  Denver  Laboratory  were  handicapped  as 
they  had  never  previously  investigated  an  explosion.  All  that 
they  could  do  was  to  take  the  statements  of  the  men  that  had 
been  in  the  plant  at  the  time  and  incorporate  the  same  into  a 
report. 

This  is  the  first  flour  mill  explosion  we  have  had  to  investigate 
since  the  explosion  in  Nebraska  in  September,  1919.  The  Ne- 
braska explosion  was  due  to  a  man  striking  a  match.  The  in- 
formation received  at  Washington  indicated  that  the  explosion 
at  Denver  started  in  connection  with  the  dust  collecting  system. 
We  had  not  previously  investigated  an  explosion  starting  in  the 
dust  collecting  system.  This  case  was  associated  directly  with 
the  collecting  of  the  dust.  The  dust  collecting  equipment  was 
drawing  the  dust  from  the  rolls  and  exhausting  into  a  dust  col- 
lector of  the  Prinz.  and  Rau  stocking  type.  I  am  going  to  read  to 
you  that  part  of  the  report  as  sent  to  us  by  the  inspectors  that 
made  the  investigation  and  also  take  from  insurance  adjust,  rs' 
report  that  part  referring  to  the  fan  as  the  cause: 

"The  fire  above  referred  to  occurred  in  the  Lbngmont 
Farmers  Milling  and  Elevator  Co.,  at  2100  20th  St., 
Denver,  Colorado,  on  January  20,  at  about  4:15  p.m.  The 
building  in  which  the  Tire  occurred  is  a  four-story  brick, 
with  basement.  The  rolls  are  on  the  second  floor  and  as 
the  grain  passes  through  these  rolls  a  current  of  air  is 
drawn  through  and  over  the  grain,  known  as  roll  exhaust. 
d  he  air  from  all  the  rolls,  twentv-t wo,  is  all  drawn  to  a 
common  trunking,  and  passes  through  the  controlling  fan, 
which  is  just  above  the  third  floor.  From  the  fan  the 
aii-    is   blow  ii    through    an    elbow   of    trunking,   of    about    6 

KM 


or  8  feet,  to  the  dust  collector  where  the  damage  occurred. 

These  trunkings  or  pipes  coming  from  the  rolls  are  all 
galvanized  iron  and  increase  in  size  as  they  advance  from 
the  rolls  to  the  fan.  This  is  necessary  as  the  main  trunk- 
ing  is  constantly  receiving  additions  from  the  various  rolls. 
The  pipe  from  the  fan  to  the  collector  was  about  12  inches 
in  diameter. 

The  fan,  which  was  operated  from  a  line  shaft  over- 
head, was  of  paddle-wheel  type  and  was  made  of  steel 
enclosed  in  steel  casing.  This  casing  was  a  part  of  the  fan 
and  revolved  with  it.  The  entire  fan  operated  inside  the 
galvanized  iron  fan  chamber.  This  fan  was  held  on  the 
shaft  with  a  key  held  in  place  with  a  set  screw.  An  ex- 
amination of  this  fan  disclosed  the  following  conditions: 
The  play  between  the  fan  casing  and  the  fan  chamber 
on  the  right  side  was  about  1  inch,  while  the  play  between 
the  fan  casing  and  the  fan  chamber  on  the  left  side  was 
nil.  At  the  same  time  the  overhanging  end  of  the  fan 
shaft  extended  about  one-half  inch  and  was  bright  and 
polished.  This  would  seem  to  indicate  that  the  fan  had 
slipped  to  one  side  about  a  half  inch,  and  in  so  doing  the 
fan  casing  came  in  contact  with  the  sides  of  the  fan 
chamber  causing  friction  which  in  turn  caused  a  spark 
which  ignited  the  dust  being  handled  by  the  fan. 

The  dust  coming  from  the  rolls  contained  not  only  dust 
from  the  outside  of  the  wheat,  but  also  an  appreciable 
amount  of  flour,  (an  estimate  of  the  amount  could  not  be 
secured)  though  the  current  is  kept  low  to  prevent  too 
much  loss  in  flour  through  this  source. 

A  Mr.  II.  Evers,  employed  in  sweeping  the  floor  at  the 
time  of  tin-  accident,  described  the  occurence  as  follow-  : 

"I  was  working  with  my  back  to  the   fan   when 

suddenly   there   was   a   big  noise       I    turned   around   at 
once  and  it   looked  like  the   whole  end  of  the  building 

was  nothing  hut  lire  and  smoke." 

In  answer  to  my  inquiry  a-  to  whether  he  noticed 
whether  or  not  the  explosion  damaged  the  dusl  collector, 
he  replied  that  he  did  imt  look  as  the  only  thing  he  was 
interested  in  at  that  exact  moment  was  -elf  preservation. 
As  the  trunking  leading  from  the  fan  to  the  collector  was 

found  on  the  floor  after  the  lire,  it   appears  that  this  part 
Was  blown  off.      It    further  appears  that   this  was  the  only 

105 


damage  done  by  the  explosion  itself.  The  fire  spread 
instantaneously  to  all  parts  of  that  floor  and  the  one  above. 
The  fire  alarm  was  turned  in  at  once  and  fire  extinguishers 
were  used  until  the  arrival  of  the  city  fire  department. 

Following  are  more  direct  answers  to  the  questions 
submitted  in  your  letter  to  the  Station,  January  29,  1920: 

The  dust  collector  was  of  the  "stocking"  type  known 
as  the  Perfection  Dust  Collector  and  manufactured  by 
Prinz  &  Rati,  having  been  installed  as  part  of  the  original 
equipment,  and  exhausted  inside  the  mill  proper.  It  re- 
ceived  the  dust  from  the  rolls. 

The  trunking  from  the  fan  to  the  dust  collector  was 
about  8  feet  in  length  and  12  inches  in  diameter.  It  formed 
an  elbow  from  the  fan  to  the  dust  collector. 

As  to  the  type  of  fan  used,  everything  was  of  steel  or 
iron. 

The  product  being  collected  consisted  of  dust  from  the 
rolls. 

The  fan  bearings  had  never  caused  any  trouble.  To 
use  the  words  of  the  miller,  "the  fan  always  worked  like 
a  charm." 

Trunking  was  made  of  galvanized  iron.  Employees, 
while  familiar  with  static  electricity,  had  never  noticed  any 
in  connection  with  this  collecting  system.  The  explosion 
itself  was  not  so  violent  as  it  appears  that  the  only  damage 
done  was  to  blow  off  the  trunking  leading  from  the  fan  to 
the  dust  collector.  No  unusual  sound  had  been  noticed 
by  anyone  prior  to  the  explosion. 

As  for  devices  to  prevent  dust  explosion,  the  miller, 
Mr.  Thompson,  staled  that  so  far  as  he  knew  no  devices 
had  ever  been  installed  for  the  purpose  of  preventing  dust 
explosions.  (Mr.  Thompson  has  worked  at  this  mill 
since  it  was  built.) 

Employees  were  familiar  with  the  possibility  of  dust 
explosions  as  Government  agents  had  visited  the  plant 
about  a  year  ago  and  lectured  on  the  subject. 

The  mill  was  in  full  operation  and  the  dust  collection 
equipment  was  working  normally. 

The  mill  is  lighted  by  electricity  and  while  a  fire  from 
this  source  i^  always  possible,  it  is  not  likely  that  this 
one  was  due  to  this  Cause,  as  the  lighting  wires  and  fixtures 

were  Frequently  inspected.    All  blue  prints,  drawings,  etc., 

of    the   flow   or   dust    collecting   system    were    destroyed    by 

106 


the  fire  and  the  miller  said  he  could  not  draw  one  from 
memory. 

Xo  settling  chambers  were  used  in  connection  with  the 
dust  collector.  The  collector  seemed  to  be  large  enough  to 
accomplish  its  purpose  as  it  had  been  operating  success- 
fully since  installed  (about  1907). 

Loss  of  life,  none;  loss  to  building,  about  $23,000; 
loss  to  machinery,  $56,000;  loss  to  stock,  $30,000. 

The  explosion  occurred  in  the  fan  and  extended 
through  a  trunking  of  about  eight  or  ten  feet,  which  was 
blown  off,  to  the  dust  collector  and  then  to  all  parts  of 
the  third  and  fourth  floors.  In  short,  the  dust  in  the 
fan  was  ignited  which  in  turn  ignited  dust  in  all  parts 
of  these  floors,  the  fire  spreading  so  rapidly  that  it 
amounted  almost  to  one  explosion  over  these  floors.  This 
was  the  first  fire  that  ever  occurred  in  this  mill. 

The  weather  on  January  20,  1920,  as  reported  by  the 
United  States  Weather  Bureau,  at  Denver,  was  as  follows : 

Temperature,  25  degrees  F.  from  10  A.  M.  to  6  P.  M. ; 
cloudy;  trace  of  precipitation  in  morning  between  2  and 
4  A.  M. ;  wind  from  N.  E.,  and  blowing  eight  miles  per 
hour  at  4  P.  M.  The  average  relative  humidity  for  the 
first  twenty  days  of  January  was  60  per  cent.  The  relative 
humidity  for  January  18.  19  and  20  was  as  follows: 

6  A.M.  6  P.  M. 

January  IS 25%  14% 

January  1'' 14','  28% 

January  20 82%  74% 

The  mill  was  steam  heated.  Xo  ventilation  was  pro- 
vided except  through  the  windows  and  the  rding 
to  Mr.  Thompson,  the  plant  miller,  were  very  likely  to 
have  been  dosed  that  ilay  as  the  relative  humidity  was 
comparatively  high  and  the  temperature  low. 

All  employees  were  considered  entirely  trustworthy. 
\o  incendiarism  or  malicious  intentions  are  suspected.'1 

From   report    of   insurance   adjust 

"The  tin-  occurred  January  20,  about  4:15  1\  M.  and 
started  on  the  third  floor  north)  :'  mill  proper 

where  a  Reliance  steel  plate  exhaust  fan  \<».  45,  16*  16 
was  working  on  roll  exhaust  and  discharging  into  a  Pei 
tion  cloth  dust  collector.     1  he  fan  U 

107 


ing  shaft,  hub  on  feather  key  and  double  set  screwed 
(mechanically  correct)  but  the  hub  slipped,  allowing  blade 
casing  to  rub  on  steel  case,  and  by  either  spark  or  flame, 
caused  an  explosion  in  fan,  blowing  iron  trunking  connec- 
tion to  dust  collector  and  explosion  continuing  in  dust  col- 
lector and  over  third  floor.  The  superintendent  says  explo- 
sion shook  the  whole  building.  They  were  prompt  in  shut- 
ting down  and  getting  their  own  equipment  into  action. 
Also,  the  fire  pump  was  started.  The  superintendent  tells 
me  the  explosion  appeared  to  fire  the  whole  third  floor,  and 
fought  the  fire  alone  until  the  city  department  arrived. 
Everything  above  the  roll  floor  was  destroyed.  About  all 
that  is  left  of  the  mill  equipment  is  twenty-two  stands  of 
rolls  (badly  damaged),  packers  and  one  line  shaft.  The 
building  is  also  badly  damaged.  About  all  the  wood  work 
and  even  the  roller  floor  will  have  to  be  replaced.  The 
walls  stood  fairly  well.  You  cannot  charge  the  fire  to 
carelessness,  for  I  think  this  fan  hub  slipped  all  at  once 
and  not  gradually,  as  the  exposed  section  of  overhanging 
shaft  shows  perfectly  bright,  and  little  or  no  warning  was 
given.  It  was  just  a  plain  mechanical  accident,  that  at 
times  cannot  be  avoided.  The  explosion  would  have  oc- 
curred using  any  type  of  dust  collector  or  dust  room,  but 
it  is  an  open  question  whether  fire  would  have  issued  with 
a  Cyclone  type  of  dust  collector." 

The  early  information  received  seemed  indefinite  and  we 
submitted  the  series  of  questions  referred  to.  The  answers  sug- 
gested that  there  might  have  been  a  possibility  of  the  explosion 
starting  in  one  of  the  rolls  instead  of  in  the  fan.  This  wasn't 
cleared  up  until  our  recent  investigation.  The  insurance  adjuster 
made  his  report  and  assigned  the  fan  as  the  cause  of  the  explo- 
sion and  the  officials  of  the  company  agreed  with  him.  That  is 
explained  in  this  way.  The  officials  of  the  company  in  a  case 
of  this  kind  usually  do  not  give  out  any  information  until  after 
(he  insurance  adjuster  makes  his  report.  Now  they  told  us 
when  this  matter  was  taken  up  with  them  recently  that  this 
explosion  could  have  started  JU81  as  readily  in  the  rolls.  One 
of  the  superintendents  told  me  one  of  the  roll  doors  was  blown 
open. 

Mr.  REED  In  connection  with  the  question  regarding  the 
proper  installation  of  suction  on  the  rolls,  I  would  like  to  hear 
the  opinion  of  the  men  regarding  just   where  this  suction  should 

108 


be   placed — above    the    roll — that    is   on    the    feeder,    or    under- 
neath  the  roll,  that  is  from  a  dust  explosion  standpoint. 

Dr.  BROWN — I  think  that  while  we  might  touch  upon  that 
now,  that  possibly  Mr.  Lind  might  bring  that  up  in  connection 
with  his  discussion  of  aspirating  systems  in  the  morning. 

Mr.  PRICE — I  would  like  to  ask  some  of  the  men  if  an 
explosion  occurred  in  a  roll,  as  the  rolls  are  designed  with 
doors,  and  the  doors  were  blown  down,  would  the  explosion  be 
of  sufficient  violence  to  reach  into  the  collector? 

Mr.  BRADY — I  knew  of  one  instance  where  it  went  up  into 
a  dust  collector  and  would  have  burned  the  mill  were  it  not  for 
the  sprinkler. 

Mr.  BODNAR — I  have  had  at  least  six  millers  tell  me  of 
dust  explosions  in  the  rolls  and  in  only  about  two  of  thes 
was  there  anything  like  a  fire  following.  In  all  cases  the  doors 
were  blown  open,  and  in  no  case  was  it  mentioned  that  the  ex- 
haust system  was  affected  or  that  the  explosion  traveled  through 
the  spouts. 

Mr.  DEDRICK — In  regard  to  the  dust  being  drawn  from 
above  or  below,  it  is  usually  the  practice  to  make  an  arrange- 
ment to  draw  the  dust  from  the  hopper  above.  It  is  a  little 
easier  connected  and  perhaps  is  the  best  way,  although  fre- 
quently provision  is  made  where  it  is  connected  below,  taking 
from  the  spouts,  and  I  don't  know  but  that  is  just  as  good  a  v. 
only  it  makes  more  trouble  to  connect  up.  Xow  in  reference  to 
the  explosions,  I  think  that  ofttimes  what  have  been  reported  as 
explosions  were  pieces  of  iron  going  through  the  rolls.  There 
have  been  cases  reported  where  there  was  shock  enough  to  force 
the  doors  open.  There  was  no  bright  flash,  only  you  could 
spark-  as  you  have  seen  sparks  struck  by  a  nail  or  a  piece  of 
metal  going  through  a  grinding  machine.  1  have  caught  one  or 
two  pieces  on  the  second  break  after  passing  through  the  lir-t 
break.  They  pre--  the  mil-  apart  and  these  come  together  again 
making  a  noise  similar  to  an  explosion  report.  Personally,  1 
never  had  an  explosion  on  a  roll,  although  1  have  come  in  contact 
with  miller-  that  have  told  me  there  was  no  possibility  of  iron 
or  anything  passing  through  and  that  they  had  a  flash  which 
opened  up  the  door.     Fortunately  in  tl  sion 

extended  no   further. 

Dr.  I'I\(  >\\  \      \-  our  time  is  getting  short  we  will  close  the 
discussion  on  this  explosion  anil  take  up  the  Manit' 
sion.    M  r.  Brady  ha-  this  subject. 

109 


EXPLOSION-  ALUMINUM  GOODS   MANUFACTURING 

COMPANY,  MANITOWOC,  WISCONSIN 

By  Paul  E.  Brady 

On  Thursday,  February  26th,  1920,  at  10:55  a.  m.,  the  city 
of  Manitowoc,  Wisconsin,  was  aroused  by  a  disastrous  dust  ex- 
plosion which  occurred  within  the  plant  of  the  Aluminum  Goods 
Manufacturing  Company.  The  blast  was  heard  for  a  distance 
of  two  miles,  and  as  a  result  of  it  six  girls  lost  their  lives,  five 
more  were  seriously  injured,  some  of  whom  may  be  maimed 
and  scarred  for  life  from  the  terrible  burns  inflicted  upon  them. 

The  property  loss  was  very  slight,  although  fire  followed  the 
explosion.  It  was  readily  checked  by  the  efficient  sprinkler 
equipment  within  the  building,  combined  with  the  excellent  work 
on  the  part  of  the  employees  who  fought  the  flames  until  rein- 
forced by  aid  from  the  city  fire  department.  The  plant  was  in 
full  operation  when  the  explosion  occurred,  and  some  800  em- 
ployees on  duty.  The  accident  happened  on  the  third  floor  of 
the  wing  known  as  "C,"  in  a  room  filled  with  some  sixty  workers, 
many  of  whom  were  girls.  One  part  of  this  room  is  set  aside 
for  the  department  known  as  the  "satin  finish,"  and  within  the 
dust  collecting  system  of  this  section  the  explosion  was  recorded. 
The  finishers,  all  of  whom  were  girls,  were  seated  at  their 
benches,  when  like  a  bolt  of  lightning,  one  blinding  flash  of  fire 
enveloped  them,  and  in  an  instant  many  were  a  mass  of  flames. 
The  shrieks  and  moans  of  the  dying  and  injured  were  beyond 
description,  and  confusion  reigned  supreme,  as  the  living  torches 
made  their  way  to  nearby  fire  escapes. 

The  plant  consists  of  three  large  semi-mill  constructed  build- 
ings, and  one  large  brick  and  concrete  building  now  under  con- 
struction. These  buildings  cover  an  area  of  one  solid  block,  and 
are  designated  as  follows:  Warehouse  and  office  building,  wings 
"A,"  "B,"  "C,"  and  "D,"  and  new  building  in  construction.  The 
warehouse  and  office  building  is  five  stories  high,  of  brick  and 
wood  construction,  and  is  used  for  the  office,  storage,  and  pack- 
ing departments.  Wings  "A"  and  "B,"  and  "C"  and  "D"  arc 
connected  to  the  warehouse  and  office  building.  In  these  wings 
the  different  processes  of  manufacturing  are  carried  on.  The 
wings  are  three-story  buildings,  semi-mill  construction.  The 
company  manufactures  a  complete  line  of  aluminum  ware  such 
as  teakettles,  teapots,  cooking  utensils  and  all  articles  which  can 
I..-  manufactured  from  aluminum.  The  aluminum  is  delivered  to 
the  factory  in  sheet  form.  The  metal  sheets  vary  in  size  and 
gauge,  ranging  in  width   from  7  to  24   inches  and  varying  in 

110 


length.  Different  gauge  metal  is  used,  depending  upon  the 
article  to  be  made,  and  ranges  from  30  gauge  to  12.  After  the 
metal  enters  the  factory  it  is  given  a  light  coating  of  grease.  This 
application  of  grease  aids  in  the  handling  of  it,  in  preventing 
tearing  and  cracking  while  in  process  of  cutting,  punching, 
stamping  and  spinning.  After  the  articles  are  shaped  they  are 
passed  through  a  naphtha,  lye,  or  acid  bath,  depending  upon  the 
article.  This  removes  the  grease  and  dirt.  They  then  are  dried, 
either  by  sawdust,  which  is  applied  by  hand,  or  in  tumblers  filled 
with  sawdust.  Four  different  finishes  are  applied,  different 
articles  requiring  different  finishes.  These  finishes  may  be  desig- 
nated as  high  polish,  satin,  acid  and  emery.  The  high  polish  finish 
is  applied  by  a  buffing  wheel  made  of  cotton  fabric.  The  buffing 
wheel  varies  in  width,  and  is  constructed  in  a  manner  to  allow 
a  free  circulation  of  air  through  it.  This  type  of  wheel  is  used 
in  preference  to  a  solid  wheel,  in  that  it  does  not  take  fire  as 
readily  during  the  polishing  process.  In  this  process  simply  a 
tallow  polishing  compound  is  applied  to  the  wheel,  and  when  the 
article  is  polished  a  waste  product  is  given  off  which  is  cared 
for  by  the  suction  in  the  hood  surrounding  the  wheel.  This 
waste,  which  consists  of  cotton  particles,  grease  and  aluminum 
dust,  forms  a  sort  of  greasy  matted  product  and  is  blown  into 
a  large  dust  house.  Past  experience  of  the  company  shows  that 
since  they  changed  the  style  of  their  buffing  wheel  in  this  de- 
partment, that  they  have  nut  experienced  any  trouble  by  fire  in 
this  suction  system.  Previous  to  this,  when  they  used  the  solid 
buffing  wheel,  they  had  an  occasional  lire,  but  never  experienced 
an  explosion  from  this  material.  It  appears,  however,  that  the 
fine  particles  in  this  product  will  ignite  readily,  in  that  a  test 
was  made  of  this  material  and  an  explosion  was  recorded.  The 
emery  finish  is  applied  by  hand,  a  piece  of  emery  cloth  being 
applied  to  the  revolving  utensil.  The  acid  finish  i<  obtained  by 
dipping  the  product  in  a  vat  of  acid  solution.  The  satin  finish 
process  is  applied  by  scratching  the  artich  with  .1  steel  brush. 

The  cause  of  the  explosion  is  attributed  t<>  a  pii 

B  &  S  iron  wire  winding  itself  around  the  blade-  of  a  blower 

fan.      This  caused  a  spark  t<>  be  struck,  which   in  turn   ignited 

the  fine  particles  of  dust.     This  conclusion 
an  examination  was  made  of  the  fan  by  C.  W.  Kenii 
resentative    of    the    State    Industrial    Commission,    Ma< 
.  along  with  offi 

explosion   occurred.    Mr.    Keniston    was    ordered    there   at    the 

request   of  the  officers   of  the   company.     In   tl  nrJme 

111 


instructions  were  issued  for  no  one  to  touch  anything  within 
the  room  where  the  explosion  occurred.  This  was  done  that 
the  industrial  commissioner  might  have  all  evidence  which 
might  aid  in  solving  the  mystery.  Mr.  Keniston  was  the  first 
to  open  the  fan  and  found  the  wire  within  it.  Just  how  the 
wire  got  into  the  fan  seems  to  be  a  mystery,  but  the  con- 
sensus of  opinion  of  those  closely  connected  with  the  inves- 
tigation is  that  the  wire  came  in  from  the  outside.  The  ex- 
haust pipe   from   the   fan   extended  out  through   the   window 


View 


lystem   showing   wire  as   found   in   fan   following  the 

brushes  used  can   be  Been  OH   lunch. 


explosion.     Buffing 


and  up  to  about  five  feet  above  the  roof  level,  and  discharged 
..in.)  the  roof  The  company  at  the  present  time  is  erecting 
a  new  building  adjacent  to  this,  and  various  guy  wires  have 
been  strung  to  the  tops  "i"  numerous  buildings  about  the  plant. 
Whether  through  carelessness  someone  laid  a  piece  of  this 
wire  on  the  mouth  of  the  exhaust  pipe,  no  one  seems  to  be 
able  to  tell.  The  construction  of  the  pipe  leading  from  the 
fan  to  the  roof  is  such  that  the  wire  coining  in  from  the  out- 
side would  have  to  pass  through   two  turns  of  45  degrees. 

112 


This  being  the  case,  it  is  quite  possible  that  the  wire  may 
have  been  lodged  in  the  pipe  for  some  length  of  time,  grad- 
ually working  down  by  the  vibration  of  the  pipe,  until  event- 
ually it  was  caught  by  the  paddles  of  the  fan  and  wound 
around  same.  Two  girls  within  ten  feet  of  the  fan,  employed 
at  a  wrapping  bench,  heard  a  noise  within  the  fan  just  prior 
to  the  explosion.  This  noise  was  heard  distinctly  on  two  occa- 
sions previous  to  the  blast.  It  appeared  to  be  simply  a  rattle 
and  one  girl  on  hearing  it  got  up  from  her  chair  and  walked 
away  from  the  fan.  Two  pieces  of  wire  were  removed ;  one 
from  the  fan  and  the  other  from  the  exhaust  pipe.  The  sup- 
position is  that  the  wire  was  broken  ;  one  piece  winding  itself 
about  the  paddles,  the  other  sticking  in  the  pipe.  The  trunk 
line  under  the  bench  leading  to  the  fan  was  cleaned  out  two 
months  previously.  Orders  were  to  the  effect  that  this  trunk 
line  was  to  be  cleaned  out  every  two  months.  The  workman 
whose  duty  it  was  to  look  after  the  cleaning  of  this  trunk  line, 
advised  that  it  was  his  intention  to  have  cleaned  same  the 
following  Saturday.  He  stated  that  at  all  times  he  used  a 
cable  in  removing  the  dust  and  dirt  from  the  trunk  line,  along 
with  a  wooden  scraper.  The  wire  found  in  the  fan  does  not 
correspond  to  the  cable  which  he  claims  to  use  in  this  cleaning 
process.  He  estimated  that  an  average  of  about  thirty  pounds 
of  dust  and  dirt  is  taken  from  the  trunk  line  every  two  months. 
A  slight  explosion  is  recorded  at  this  plant  in  the  same 
fan  and  .suction  system  during  the  summer  of  1919.  A  work- 
man was  engaged  in  cleaning  out  the  suction  system  of  the 
satin  finish  department  prior  to  the  time  that  the  finishers 
came  on  for  the  day's  shift.  lie  had  the  fan  running,  and 
during  the  cleaning  process  tin-  wire  which  he  was  using  came 
in  contact  with  tin-  fan  blade.  This  struck  a  spark,  and  an 
explosion  occurred  which  broke  open  the  trunk  line  whi 
it  entered  the  fan.  After  this  occurrence,  the  superintendent 
instructed  him  that  in  the  future  this  trunk  line  must  not 
be  cleaned  while  the  plant  was  in  operation.     The  workman 

advised  that  from  then  on  lie  made  it  a  practice  to  comply 
with  these  Orders  and  generally  cleaned  the  trunk  line  when 
the  plant  was  down  on  a  Saturday  afternoon. 

In    tlie    satin    finishing  department,    some    twenty-live    i^irl> 

are  employed.    This  department  is  located  in  a  room  200  I 
long  and  50  feet  wide.     It  occupies  a  littl(  third  of 

the  south  end  of  the  room,  while  the  balance  of  the  space  i- 
used  for  the  dipping  and  wrapping  departments.     Some  thirty 

113 


other  people  work  in  the  room,  but  all  the  employees  burned  or 
injured  worked  in  the  finishing  department.  Nine  lathes  were 
used  in  the  satin  finish  process.  These  machines  were  placed 
on  a  long  wooden  bench,  and  two  girls  employed  to  a  mahine. 
The  machine  consisted  simply  of  a  spindle  30  inches  long,  on 
which  was  placed  a  steel  brush  at  each  end.  The  satin  finish 
or  scratch  finish  was  applied  by  placing  the  aluminum  ware 
against  the  revolving  steel  brush.  During  this  process  fine 
particles  of  the  aluminum  are  removed.  This  creates  what  is 
known  as  aluminum  dust,  and  for  sanitary  reasons  a  suction 
system  was  installed  to  aid  in  the  removal  of  this  dust  and 
prevent  this  large  room,  with  its  many  workers,  from  being 
compelled  to  inhale  it. 

Surrounding  the  brushes  were  hoods  connected  by  a  3-inch 
pipe  to  a  main  trunk  line.  This  trunk  line  averages  12  inches 
in  diameter.  It  was  connected  to  a  36-inch  suction  fan  with 
a  16-inch  opening,  and  drew  the  dust  from  the  various  ma- 
chines and  discharged  it  to  the  atmosphere  outside.  The 
trunk  line  extended  underneath  the  bench  and  varied  in  dia- 
meter from  6]/2  to  16  inches.  The  fan  was  constructed  of 
steel  and  had  a  steel  casing.  It  had  a  speed  of  700  R.  P.  M., 
and  discharged  through  a  12x12  opening.  The  first  three 
machine  hoods  were  connected  separately  to  the  trunk  line, 
while  the  balance,  or  six  machine  hoods,  were  connected  in 
pairs,  one  trunk  leading  from  the  trunk  line  and  then  separat 
ing,  one  line  each  to  the  hood.  Such  a  connection  seems 
to  lead  to  the  supposition  that  the  girl  to  the  left  of  the  ma- 
chine was  invariably  the  one  most  severely  burned.  This  is 
due  to  the  fact  that  a  connection  of  this  type  had  a  more  direct 
entry  from  the  trunk  line  to  the  hoods  of  the  machines,  and 
when  the  flash  occurred  the  flames  more  readily  entered  the 
left  hood. 

Tin-  reporl  of  the  explosion  was  heard  for  a  distance  of  two 
miles.  No  damage  was  reported  to  outside  property.  Owing  to 
the  large  window  area  of  the  room  in  which  tin-  explosion 
occurred,  the   force  easily  made  its  way  to  tlu-  outside.     It   is 

quite   probable   had   this   plant    been   equipped    with    little    window 

.    that    the    side    walls,    which    wen-    bulged,    no    doubt    would 

have    given    wa)     entirely.      Three    doors    were    blown    oil    their 

hinges,  and  one   oil   ean   blown    inlo   the  ceiling.      It   appears  that 

in    wenl    straight   up,  as  the  spout    Of   the   ean   stuck    into  a 

crack  in  the  ceiling. 

The     following    recommendations     were    made:      The    suction 

114 


system  on  a  satin  finishing  system  should  be  such  that  no  dust 
would  accumulate  in  any  of  the  suction  pipes.  The  system  should 
be  so  constructed  that  there  would  be  no  accumulation  of  dust 
at  all.  In  the  system  that  was  in  use,  some  thirty  pounds  of 
dust  would  accumulate  in  the  main  trunk  line  every  two  months. 
This  brings  out  the  fact  that  maybe  the  fan  was  not  large  enough 
to  clear  the  size  of  pipes  that  they  were  using.  A  smaller  trunk 
line,  no  doubt,  would  have  been  kept  clean  with  the  size  of 
fan  they  were  using.  Where  dust  is  allowed  to  accumulate  like 
it  did  in  this  trunk  line,  it  simply  adds  ammunition  to  a  blast 
should  a  spark  be  struck  within  that  system.  Experience  shows 
that  no  wire  should  be  used  to  clean  out  a  trunk  line  of  this 
nature.  This  company  experienced  a  minor  explosion  from 
this  source  about  eight  months  previous  to  this  one.  It  would 
seem  practical  to  run  a  trunk  line  handling  material  of  this 
nature  overhead  of  the  machines  instead  of  along  the  floor. 
In  this  instance  the  trunk  line  ran  along  at  the  feet  of  tin- 
operators,  and  the  blast  blew  part  of  it  to  pieces,  giving  the 
flames  a  chance  to  envelop  the  workers  very  readily.  Had  this 
trunk  line  been  up  above  the  heads  of  the  operators  some  six 
or  eight  feet,  it  is  possible  that  the  flames  might  not  have  reached 
them  so  readily  as  when  they  burst  forth  at  their  feet.  We 
believe  it  advisable  to  perhaps  cut  down  the  units  in  such  a  way 
that  instead  of  having  one  large  suction  system  to  handle  all 
the  machines,  that  more  individual  fans  be  used  to  a  unit.  In 
other  words,  make  separate  units.  It  might  be  desirable  to  plac 
the  fan  near  the  ceiling  above  the  trunk  line,  so  that  the  eurrent 
of  air  entering  it  will  always  be  drawing  up.  This  might  elimi- 
nate the  danger  of  a  piece  of  metal  being  carried  into  it  and 
striking  a  spark. 

Mr.  BATES — What  was  the  material  of  the  wire  found  in 
the  fan. 

Mr.  BRADY — It  was  iron  wire. 

Mr.  PRICE  I  -aw  the  wire  at  Madison.  It  was  thicker  than 
telephone  win-.  It  might  be  used  in  connection  with  construction 
work  such  as  they  were  doing. 

|),-.  DUVEL  1 1  has  just  occurred  to  me;  would  it  not  In- 
worth  while  to  have  an  analysis  made  of  that  wii 

Dr.  BROWN     It  might  be  to  determine  accurately  the 
of  wire;  1  am  sure  we  would  l.c  glad  to  have  n  done. 

115 


Mr.  PRICE — The  Wisconsin  State  Industrial  Commission 
is  now  preparing  a  report  and  when  that  report  comes  in,  the 
information  will  practically  be  covered. 

Mr.  BATES — I  have  not  been  able  to  satisfy  myself  as  to 
a  metal  like  this  exploding.  I  cannot  understand  how  aluminum 
dust  under  any  condition  would  cause  an  explosion.  I  would 
like  to  see  one. 

Dr.  BROWN — Come  up  to  the  laboratory  and  we  will  show 
you. 

EXPL(  )SION  IN  FEED  MILL  AND  ELEVATOR,  CURTISS 
(.RAIN  CORPORATION,  BUFFALO,  N.  Y. 

By  H.  J.  Helmkamp. 

This  explosion  occurred  September  12,  1919  at  5:23  P.  M. 
resulting  in  injuries  to  three  men  and  property  damage  to  the 
extent  of  about  $20,000.  The  plant,  which  was  of  brick  construc- 
tion, consisted  of  the  following  units  :(1)  a  3  story  warehouse,  (2) 
a  5  story  building  used  as  mill  and  elevator,  (3)  a  2  story  structure 
used  for  making  molasses  feeds,  (4)  a  1  story  warehouse  for 
bag  storage,  (5)  offices  (of  wooden  construction). 

In  unit  No.  2  the  grinding  was  done  on  the  first  floor.  From 
the  second  to  the  fourth  floor  were  crib  storage  bins  and  one 
large  metal  scale  bin  extending  from  the  second  to  the  fourth 
floor.  The  fourth  floor  was  used  as  a  bin  floor  and  was  equipped 
with  tin-  rlcaning  machines.  Lofter  heads  were  on  the  fifth  floor, 
also  a  receiving  separator  and  cyclone  dust  collector. 

Planl  was  used  for  the  storage  «»t'  grain  both  in  sacks  and  in 
bins  and  for  the  manufacturing  of  mixed  feeds  and  molasses 
feeds.  The  elevator  was  equipped  with  two  lofter  legs,  one  for 
receiving  and  one  for  loading  out  grain.  The  elevator  process 
was  similar  to  other  plants  of  this  type.  The  investigation  showed 
that  the  outside  of  the  elevator  legs  and  the  outside  of  the  man 
lift  were  seorehed.  Manns  seem  tO  have  traveled  up  around  the 
metal  scale  bin  to  the  fourth  floor  where  the  explosion  oecurred. 
The  force  of  the  explosion  blew  out  part  of  the  west  wall  on  the 
fourth  floor  and  blew  oil'  part  of  the  roof  of  the  lofter  room  at 

the  top  of  the  building. 

The  point  at   which  the  explosion  originated  or  its  cause  was 

no i   definitely  determined.     (  me  theory  advanced   was  that   the 
muslin  cover  around  the  motor  on  the  fourth  floor  was  ignited 

116 


by  a  spark  and  the  flash  communicated  to  the  other  floors  through 
the  various  openings.  Upon  running  the  motor,  however,  two  days 
later,  for  a  period  of  two  hours,  it  was  found  to  operate  satis- 
factorily. 

Other  theories,  such  as  the  explosion  originating  in  the  eleva- 
tor leg  and  also  the  possibility  of  a  workman  striking  a  match 
while  preparing  to  leave  the  building,  were  advanced.  The  great- 
est damage,  however,  was  done  at  the  top  of  the  building,  which 
would  indicate  that  the  explosion  might  have   traveled   in   that 


D       ige  to  upper  floors  resulting   from  duel 
in  a  feed  mill. 

direction.  The  burning  of  the  muslin  cover  over  the  motor  on  the 
fourth  floor  tnighl  have  been  caused  by  the  fire  accompanying  the 
explosion.  From  evidence  obtained  at  the  investigation  it  Is  be- 
lived  that  the  fire  started  from  some  unknown  cause  on  the  firsl 
floor  near  the  lofter  leg  and  propagated  up  to  the  fourth  floor 
about  the  metal  scale  bin  and  upon  reaching  this  floor  ignited  the 
dust  thai  was  in  suspension  in  the  air,  thereby  causing  tl. 
plosion. 

117 


Dr.  BROWN — Is  there  any  discussion  on  this  explosion?  If 
not,  there  is  one  man  from  whom  we  would  like  to  have  a  few 
remarks,  and  that  is  Mr.  Boerner,  who  has  been  associated  with 
us  in  the  Department  of  Agriculture.  We  have  had  very  pleasant 
associations  with  Mr.  Boerner's  staff  in  the  Supervision  Offices 
throughout  the  country.  I  am  "sure  we  would  be  glad  to  have 
a  few  remarks  from  Mr.  Boerner. 

Mr.  BOERNER — Mr.  Chairman :  I  have  been  listening  with 
a  great  deal  of  interest  to  the  discussions.  There  are  a  great 
many  features  brought  out  in  the  work  which  are  worth  while  get- 
ting to  the  people.  When  you  were  talking  a  while  ago  about  the 
educational  phases,  of  the  need  of  getting  this  work  to  the  high 
schools,  it  occurred  to  me  that  one  source  that  was  not  mentioned 
was  that  of  the  grain  supervision  force  of  the  Bureau  of  Markets. 
They  are  constantly  working  with  the  elevator  people,  and  some 
of  them  who  are  specializing  in  particular  lines  of  the  work,  are 
at  the  elevators  entirely,  and  it  would  be  doing  a  lot  of  good  to 
get  this  work  to  these  people.  The  whole  problem  is  of  interest 
to  our  grain  section  of  the  Bureau  of  Markets.  I  am  connected 
with  the  investigational  work,  and  we  are  planning  this  coming 
year  to  take  up  the  question  of  elevator  construction  design;  not 
so  much  the  question  of  detailed  specifications,  but  general  prob- 
lems involved,  especially  in  the  Pacific  Northwest  where  they  are 
changing  from  bag  to  bulk  system ;  and  apparently  they  should 
not  forget  this  dust  explosion  prevention  work.  Surely  that  is 
a  pertinent  feature  in  making  up  our  designs,  and  there  is  no 
question  but  that  there  would  be  a  great  deal  of  use  for  it.  Our 
office  is  receiving  requests  every  day  for  designs.  If  we  had  this 
in  shape  so  that  we  could  use  it  in  that  connection,  we  would  make 
very  good  use  of  it. 

Dr.  BROWN — I  am  sure  we  appreciate  Mr.  Boerner's  re- 
marks. I  might  say  we  have  been  making  more  use  of  these 
inspectors  than  Mr.  Boerner  realizes.  It  has  been  my  experience 
in  holding  our  special  meetings,  that  the  supervision  officers  have 
been  counted  on  in  getting  the  people  to  the  meeting,  and  the 
supervisor  particularly.  In  many  cases  thej  have  had  their  entire 
force  at  the  meeting.  1  am  sure  we  will  be  pleased  to  accept  Mr. 
Boerner's  kind  offer  to  extend  the  activities  through  this  force  to 
get  information  to  them.      For  your  information.  I  might  state  that 

we  are  anticipating  getting  oul  a  couple  of  publications  shortly, 

and  we  would  be  glad  to  have  them  distributed  to  all  of  these  men. 

We  have  two  other  explosions  to  consider  this  afternoon,  and  I 

118 


will  ask  Mr.  Riley  to  tell  us  about  the  explosion  at  the  "H — O." 
Mill  at  Buffalo. 

"H-O"  MILL  EXPLOSION  AT  BUFFALO,  N.  Y. 

By  E.  L.  Riley. 

This  explosion  took  place  the  21st  of  November,  while 
certain  changes  were  being  made  in  a  steel  leg  located 
between  two  steel  tanks.  The  only  opening  in  the  boot  of 
this  leg  was  a  small  hand  hole  at  one  side  and  when  the  leg  be- 
came choked,  it  took  some  time  to  clear  it,  due  to  this  small 
opening.  The  superintendent  on  the  day  following  a  bad  choke 
in  this  leg,  gave  instructions  to  the  millwright  to  cut  a  square 
out  of  the  front  of  this  boot  and  place  a  slide  in  there,  so  that 
the  leg  could  be  easily  cleared,  if  another  choke  should  occur. 
The  millwright,  thinking  it  perfectly  safe,  had  a  man  bring  an 
acetylene  out  lit  in,  to  burn  this  square  out  of  the  boot  and  while 
this  man  was  engaged  at  this  task  at  the  boot  of  the  leg,  another 
man  was  at  work  at  the  head  of  the  leg  removing  a  short  spout 
leading  from  the  head  of  the  leg  to  a  steel  conveyor.  The  top 
of  this  leg  had  been  removed  so  that  the  man  working  on  the 
spout  at  the  head  of  this  leg  could  see  better.  The  man  at  the 
boot,  after  burning  the  square  far  enough  through  as  he  thought 
so  that  a  few  taps  of  a  hammer  would  knock  it  out,  extinguished 
the  acetylene  torch  and  was  coiling  up  the  hose,  preparing  to 
depart,  when  one  of  the  men  started  to  hammer  on  this  square, 
intending  to  knock  it  out.  At  the  same  time  the  man  at  the  head 
of  the  leg  started  to  hammer  on  the  short  spout  that  he  was  try- 
ing to  remove.  An  explosion,  or  in  my  opinion,  two  explosions 
look  place  at  this  time,   that  wrecked  this  7:  teel   leg  and 

burned  three  men  at  the  boot  of  the  leg  and  one  man  who  was 
working  at  the  head.  The  explosion  or  explosions,  went  upward 
through  the  back  of  the  leg  and  burst  the  steel  housing  for  a 
distance  of  about  30  feet,  starting  at  a  point  about  half  way  up 
the  leg.  It  i^  my  opinion  that  a  small  explosion  took  place  in 
the  boot  when  the  dust  accumulation  there,  which  had 
ignited  by  the  intense  heat   from  the  acetylene  torch,  iwn 

into   suspension   by   the  hammering  on   the   boot,   ami   the 
from  this  first   explosion   shooting  upward  came   in   C  •  ith 

the  dust  cloud  created  by  the  man  hamnn  ait 

leading  from  the  head  of  the  leg,  and  another 
place,  this  last  explosion  bursting  through  tl  md 

doing  tin1  must   damage      I   believe   tin-   explosion    will 

11') 


means  of  preventing  a  similar  occurrence  at  this  plant,  for  it  has 
proven  our  contention  that  open  flames  should  never  be  allowed 
in  any  part  of  a  mill  or  elevator,  due  to  the  existing  hazard  of 
dust  explosion  and  fire  in  these  plants. 

Dr.  BROWN — Is  there  any  discussion  on  this  particular 
explosion?  I  am  sure  it  is  an  interesting  case  and  one  on  which 
we  could  get  quite  definite  information. 

Mr.  RILEY — I  might  state  that  three  men  were  burned  at 
the  boot,  and  one  man  working  at  the  top  was  more  or  less 
seriously  burned. 

Dr.  BROWN — An  interesting  fact  brought  out  in  that  ex- 
plosion is  that  the  top  of  the  elevator  leg  was  open,  still  the 
explosion  occurred  and  blew  apart  a  portion  of  the  casing.  Is 
there  any  other  discussion  on  this  subject?  If  not,  we  will  ask 
Mr.  Riley  to  discuss  the  explosion  at  the  Spice  Works  in  Cin- 
cinnati. 

Mr.  DEDRICK — It  would  seem  that  if  the  leg  were  open  all 
the  way  that  it  would  give  it  an  opportunity  of  getting  a  vent ; 
that  the  pressure  would  go  up,  particularly  on  the  back  of  the 
leg  with  the  buckets  down  would  make  it  more  obstructive  than 
if  it  had  been  in  the  front  of  the  leg. 

Dr.  BROWN — Any  other  discussion  on  this  explosion  ? 

Mr.  BODNAR — That  case  makes  me  think  of  the  possible 
fact  that  small  openings  or  vents  in  bins  would  hardly  be  effective 
enough  to  prevent  building  up  of  pressures,  i.  e.,  that  the  pres- 
sures would  be  strong  enough  to  blow  bins  apart  as  in  the  Port 
Colborne  explosion,  and  the  elevator  construction  that  I  illus- 
trated the  first  day  would  seem  to  me  to  be  a  better  method  of 
venting  bins  than  merely  by  means  of  a  small  pipe  vent.  Mr 
Riley's  explosion  there  made  me  think  of  that,  and  I  thought  it 
would  be  well  to  bring  this  idea  to  your  attention. 

NEWTON  TEA  AND  SPICE  COMPANY  FIRE, 
CINCINNATI,  I  >HI<  >.  JAN.  17,  1920. 

By  E.  L.  Riley. 

On  January  17,  1920  four  firemen  were  killed  and  thirteen 
injured,  when  apparently  an  explosion  in  the  burning  mills  of  the 
Newton  Tea  and  Spice  Company  at  Cincinnati,  Ohio,  blew  oul 
the  easl  wall  of  the  structure.  Firemen  had  been  fighting  the  fire 
for  approximately  thirty  minutes  before  this  wall  fell,  and  facts 

120 


brought  out  at  this  investigation  lead  us  to  believe  that  this  plant 
had  been  burning  for  hours  before  being  discovered.  I  do  not 
believe  that  this  fire  started  from  a  dust  explosion  or  that  the 
explosion  was  due  to  the  dirty  condition  of  the  plant,  for  reports 
of  the  Ohio  Inspection  Bureau  show  that  the  plant  was  in  clean 
condition  at  the  time  of  their  last  inspection.  The  ground  spices, 
after  coming  from  mills,  were  stored  in  wooden  barrels  and  I 
believe  that  these  barrels  of  spices,  which  were  uncovered,  fell 
with  the  floor  on  which  these  barrels  were  stored  and  the  result- 
ing clouds  of  spice  coming  in  contact  with  the  flames  caused  the 
explosion  that  blew  out  the  wall  on  the  firemen. 


Fire  an  at  plant  of  Newton  Tea  and   S]  I  incinnati,  Ohio.     At  i 

right  can  be  seen  l>ri<l«r   from  which  tin  nun   were  fighting  tlu-  fire   when   tli 
out  hy  explosion  of  spice  dtUt. 

Dr.  BR<  )\\  X  Arc  there  any  questions  or  discussion  re 
garding  this  explosion  ?  It'  not,  1  think  this  will  close  our  program 
for  this  afternoon.  We  have  a  pretty  full  program  for  to-morrow 
morning.  Wc  did  not  get  time  to  finish  all  we  had  for  today 
because  we  did  not  get  here  on  time,  so  1  am  going  to  ask  you 
io  get  here  by  9  o'clock  so  that  we  ma;  Lrted  promptly. 

Meeting  adjourned  until  9  a.  m.  Saturday,  April  24. 


i   i 


SATURDAY  MORNING  SESSION,  APRIL  24,  1920 

E.  N.  Bates,  Presiding. 

Mr.  BATES — The  first  paper  this  morning  is,  by  Air.  Witmer, 
on  the  subject  of  ''Suction  versus  Bucket  Elevating  in  Handling 
of  Grain." 

"SUCTION    VS.   BUCKET   ELEVATING   IN   HANDLING 

OF  GRAIN. 

By   Geo.   D.   Witmer. 

The  method  generally  employed  today  for  the  handling  of 
grain  in  this  country  is  by  bucket,  conveyor  and  spout.  By  choke- 
ups,  friction  and  hot  journals,  the  bucket  elevation  has  been  the 
cause  of  a  number  of  plants  being  destroyed  by  fire  and  explosion. 
On  the  working  floor  where  the  grain  is  removed  from  the  car,  it 
is  generally  dropped  a  distance  of  from  4  to  6  feet,  and  at  this 
point  a  large  quantity  of  dust  escapes,  becoming  suspended  in  the 
air  and  finally  lodging  on  beams  and  ledges.  While  moving  a 
large  quantity  of  grain  by  this  method,  the  air  becomes  extremely 
heavily  laden  with  dust  and  the  working  conditions  are  bad.  It 
is  possibly  due  to  these  bad  features  in  connection  with  handling 
grain  by  bucket  elevation,  that  the  air  conveying  method  is  gaining 
prominence  and  is  favorably  looked  upon  by  some  of  our  grain 
men. 

In  Europe  more  than  sixty  per  cent,  of  the  import  grain  is 
handled  by  suction.  In  this  country  only  a  very  small  quantity 
of  grain  is  handled  in  this  way. 

The  pneumatic  or  air  conveyor  is  simple  in  construction.  There 
are  two  principles  :  ( >ne  is  suction  and  the  other  pressure.  Where 
suction  is  used,  a  partial  vacuum  is  maintained  within  an  enclosed 
tank  by  a  motor  driven  exhauster.  The  conveyor  duets  which  are 
provided  with  flexible  intakes  or  self  Feeding  nozzles,  lead  from 
the  ear  or  vessel  to  the  tank.  The  high  velocity  of  the  air  blast 
within  the  duet  conveys  the  grain  which  when  reaching  the  tank 
becomes  released  and  drops  to  the  bottom,  dischargil  g  through  a 
rotary  discharge  gate  directly  to  the  storage  bins,  Or  may  again 
he  blown  to  some  other  part  of  the  building  by  Utilizing  the  air 

blast   I'rom  the  discharge  side  of  the  exhauster.     In  this  second 

operation,   however,   pressure    would    he   used    instead    of    SUCtion. 

A  dust  collector  may  he  installed  and  a  complete  separation  made 

of  the  dust  and  air  which  is  given  off  by  the  exhausl   from  the 
vacuum  tank. 

1  " 


With  the  suction  method  the  grain  is  drawn  directly  from  the 
car  or  vessel  and  delivered  to  any  part  of  the  building.  The 
distance  the  grain  may  be  conveyed  depends  entirely  on  the 
amount  of  power  used.  One  elevator  company  which  uses  both  the 
bucket  elevator  and  suction  system  for  the  elevation  of  their  grain, 
makes  the  following  comparison  in  relation  to  capacity:  A  100 
H.  P.  electric  motor  is  required  to  operate  their  bucket  elevators 
and  another  motor  of  the  same  size  is  attached  to  the  suction 
system.  During  an  hour's  run  on  wheat,  the  elevators  handled 
15,000  bushels  and  the  suction  2,500  bushels,  or  one-sixth  Un- 
capacity of  the  bucket  elevators. 

Due  to  the  automatic  nozzles  used  in  connection  with  the 
suction  system,  several  outstanding  points  are  worthy  of  con- 
sideration. 

Cars  are  unloaded  without  the  removal  of  grain  doors. 
It  eliminates  power  shovels  in  cars  and  the  holds  of  vessels. 
It  eliminates  waste  and  thoroughly  removes  all  grain. 
Makes  possible  a  close  separation  between  wet  and  dry  grain. 
Makes   it  possible  to  remove  grain   from  a  vessel   in  rainy 
weather. 

Eliminates  danger  of  damage  to  a  small  vessel,  or  barge,  by 
accidental  lowering  of  the  heavy  marine  leg,  or  from  the  vessel 
riding  on  the  wash  of  passing  steamers. 

Betterment  of  labor  conditions  and  eliminating,  to  a  great 
extent,  the  dusl  and  fire  hazard. 

The  Pressure  System,  which  may  possibly  be  called  a  grain 
blower,  is  not  intended  for  the  removal  of  grain  from  a  car  or 
vessel;  but  when  the  grain  is  delivered  to  its  hopper  or  supply 
tank,  its  work  is  similar  to  that  of  the  suction  system,  with  the 
exception  of  the  suction  nozzle.  The  grain  when  spouted  or 
delivered  t<>  the  hopper,  passes  into  a  spiral  conveyor  which 
carries  it  upward  at  an  angle  of  45  degrees,  and  feeds  it  through 
a  valve  into  the  blower  discharge  immediately  underneath.  From 
this  point  the  -rain  and  air  travel  through  an  air  duct  to  a 
receiving  tank  or  cleaner  which  may  be  located  above  tin 
bins  or  any  other  pari  of  the  building,  when-  the  grain  i:  intended 
to  be  delivered.     There  are  no  moving  pans  in  the  receiving  tank 

that  operate  mechanically  and  it-  operation  i-  similar  to  that  i 

lone    duSl  Collector.      The   chaff,    dirt    and    dust,    I  hter 

than  the  -rain,  will  not   have  the  same  momentum,  and  .. 
entering  the-  cleaner  will  immediately  bee  arated  and  tr 

with  the  air  through  the  discharge  to  the 
being  heavier   will   drop   t«»   the   bottom   and   pass   through   an 

123 


opening  or  spout  to  storage.  Should  it  be  desired  to  collect  the 
chaff  and  dirt  escaping  with  the  air,  a  dust-collector  could  be 
installed  and  this  material  again  recovered. 

A  grain  blower  may  be  installed  inside  or  outside  of  a  build- 
ing and  may  be  portable.  It  will  convey  or  deliver  grain  from 
one  building  to  another,  from  elevator  to  mill,  from  wagon  to 
storage,  and  may  be  used  for  the  loading  of  grain  into  cars.  All 
that  is  necessary  is  to  connect  a  pipe  leading  from  the  blower 
to  whatever  place  the  grain  is  intended  to  be  delivered.  The 
capacity  of  a  grain  blower,  like  the  automatic  suction,  depends 
entirely  on  what  kind  of  grain  is  handled  and  the  distance,  and 
height  to  which  it  is  delivered. 

In  the  movement  of  grain  with  either  of  the  above  mentioned 
methods,  wheat  and  rye  require  the  most  suction  and  pressure. 
Corn,  although  weighing  a  little  less,  is  handled  much  faster  with 
the  same  speed  and  power.  Oats,  being  much  lighter,  handle  still 
faster  than  corn.  The  reason  for  this  difference  is  that  the  corn 
kernel  is  much  larger  in  size  than  wheat  or  rye  and,  therefore,  has 
a  much  greater  area  exposed  to  the  air  blast. 

Elbows  in  the  air  ducts  or  pipe  lines  should  be  avoided  where- 
ever  possible  and,  when  necessary,  should  have  a  long,  easy 
curve  so  as  to  give  the  least  resistance  to  the  passing  grain. 
Grain  in  the  air  duct  travels  at  a  great  velocity,  and  in  striking 
a  short  curve  or  elbow  will  have  a  tendency  to  rebound.  To 
overcome  the  rebounding  and  the  extra  friction  consumed  in 
forcing  the  grain  through  the  elbow  at  its  initial  velocity,  it  is 
necessary  to  have  increased  air  pressure  or  suction,  and  this 
means  an  increase  of  power. 

Grain  generally  is  in  such  a  condition  that  it  could  be  im- 
proved upon  every  time  it  is  handled.  The  time  is  long  past 
when  -rain  in  poor  condition  will  bring  the  same  price  as  that 
<>\  a  No.  1,  therefore,  the  improving  and  conditioning  of  the 
-rain  in  a  simple-  way  should  be  of  importance.  When  grain  is 
conveyed  by  either  tin-  suction  or  Mown-  method,  we  might  say 
every  time-  it  is  handled,  it  receives  an  airing,  cooling  and 
cleaning. 

Mr.    BATES      This    paper    has   been    of    particular    interest 

to  me  as  I  have  made  some  little  study  of  this  question  of 
handling  grain  by  the  different  methods  and  it  certainl)  is  a 
well  prepared  paper,  and  the  advantages  enumerated  seem  to 
j  complete.  I  was  interested  in  comparing  the  figures  that 
Mi-.  Witmer  gave  For  the  elevation  by  suction  with  figures  I 

124 


recently  saw  in  a  magazine,  in  which  they  claimed  that  the 
European  pneumatic  elevators  required  about  one  horse 
power  per  ton  of  grain  handled  per  hour,  which  seems  to  be 
a  fairly  general  rule.  Twenty-five  hundred  bushels  would  be 
a  little  less  than  one  hundred  tons.  These  elevators,  I  beli< 
mechanically  are  very  inefficient.  As  I  estimated  the  height  to 
which  they  would  raise  the  grain,  the  elevator  on  which  1 
figured  was  about  ten  per  cent,  efficient.  A  certain  pneumatic 
farm  elevator  on  the  market  is  a  combination  of  suction  and 
blowing.  They  suck  the  grain  out  of  the  wagon  box  or  from 
whatever  they  are  taking  the  grain,  run  it  through  a  revolving 
chamber  and  then  by  the  blast  of  the  fan  blow  it  into  the  bins. 
I  believe  this  machine  worked  out  about  7)  2  per  cent,  efficient. 
It  would  look  as  though  the  air  suction  method  was  a  rather 
expensive  affair  as  far  as  mechanical  energy  is  concerned, 
which  is  exactly  true.  It  is  just  a  question  of  whether  that 
est  of  power  outweighs  the  flexibility  and  desirability  of 
having  your  grain  handled  that  way.  We  have  a  few  minutes 
more  for  discussion  here. 

Mr.  PRICK — The  method  applied  by  engineers  in  the 
suction  collector  was  discussed  last  year  at  our  Chicago  con- 
ference.    We  recently  witnessed  a  demonstration  of  handling 

materials  in  which  there  was  a  great  deal  of  foreign  substance. 
The  dust-collector  was  between  the  source  of  collection  and 
the  fan.  I  should  like  to  ask  Mr.  Witnier  whether  from  his 
observation  of  a  system  of  this  kind  in  some  of  the  eastern 
industrial    plants,   he    feels    that    it    might    be    extended    to    the 

handling  <  »f  grain  ? 

Mr.  WITMER — Possibly  it  could.  These  machines  are 
gi\ing  satisfaction  on   the  handling  of  pulverized   materials, 

in    fact   any   material    where   it    is   desired    to   collect  vcr 

the  dust,  such  a^>  lime,  ash,  fertilizer,  etc.  But  this  material 
handles  considerably  easier  than  wheat,  rye,  or  corn.    Wheat 

and    rye    are    the    hardest    materials    t<>    handle    and    requip 
great  amount  of  power.      In  the  handling  of  -rain  an  ordin 
cyclone  dust  collector  would  possibly  be  used  instead  of  the 
long  cloth  tube  recoverers  used  in  connection  with  the  hand! 

ing  of  pnh  erized   material. 

Mr.  PRU  I  It  has  become  apparent  that  dust  has  a  com- 
mercial value  per  pound.  The  lab  ing 
samples  of  elevator  dust  which  we  understand  they  find  an 


high  grade  or  high  rating  for  cattle  feed.  It  might  be  some 
inducement  to  recover  the  dust. 

Dr.  DUYEL — I  don't  remember  the  figures  we  have  had, 
but  we  have  had  a  number  of  samples  analyzed  and  they  are 
valuable.  Every  time  I  go  around  an  elevator  I  can't  help 
but  feel  that  the  waste  of  valuable  material  is  excessive.  That 
is  one  reason  I  am  particularly  interested  in  this  dust-collect- 
ing question.  I  think  that  the  time  is  coming  when  there 
will  be  dust-collecting  systems  on  -elevators  as  they  unload 
the  cars,  regardless  of  the  attitude  taken  by  state-weigh- 
masters  :.nd  other  state  officials.  Some  method  is  going  to 
be  provided  to  take  out  dust  and  make  suitable  working  con- 
ditions wherever  we  have  dust.  It  should  not  be  wasted. 
That  is  one  thing  elevator  people  don't  realize.  It  is  the  same 
thing  you  get  back  to  by  putting  cleaners  on  threshing  ma- 
chines. As  the  farmer  has  the  dirt  taken  out  he  doesn't 
worry  about  it.  That  is  one  reason  I  have  always  been 
opposed  to  a  modification  in  the  wheat  standards,  raising  the 
dockage  to  one  per  cent.  There  is  no  inducement  to  remove 
the  dust. 

Mr.  1 1 1  BBARD — The  market  value  of  elevator  dust  at  the 
nt  time   is   five  to  eight   dollars  per  ton.     One  plant  in 
Chicago  produces  8  to  10  tons  per  day. 

Dr.  BROWN  It  Was  my  pleasure  some  time  ago  to  visit 
and  see  in  operation  one  of  these  types  of  installations  of 
which  Mr.  Price  has  spoken,  and  while  that  was  being  used 
for  the  handling  of  fertilizer  products,  as  for  instance  ground 
tankage  and  other  substances  used  in  the  making  of  fertilizers, 
the  man  who  was  operating  it  had  been  over  two  years  in  an 
elevator  and  knew  something  of  the  problems  oi  handling 
grain.  He  felt  that  thai  system  would  be  very  effective  and 
operate  verj  efficiently  in  the  handling  of  grain.  One  objec- 
tion  which  has  ben  raised  to  that— I  don't  know  whether  it  is 
altogether  real  or  only  apparent  seems  to  have  been  to  the 
fad    that   the   grain    goes   in    straight,   perpendicular   to   the 

diameter,  v  e  might  say,  and  Strikes  against  baffle  plates  on 
the  far  side,  the  feeling  being  that  in  SO  doing  the  grain  would 
be  broken  and  the  abrasive  loss  would  be  great.  This  man 
felt  that  that  was  not  an  objection  because  the  grain  was  not 
moving  at  a  velocity  comparatively  speaking  any  higher  than 

the  velocity  attained  in  dropping  it  into  deep  pits  or  other 
mi'  apparatus   where   the  grain   is   really   thrown   some 

126 


distance.  However,  he  did  raise  the  question  of  mechanical 
efficiency.  He  felt  that  the  installation  as  used  there  was 
really  too  expensive  to  pay  for  itself  in  operation. 

Mr.  WITMER— In  the  installation  that  I  looked  into,  the 
receiving  pipe  entered  at  the  side  of  the  tank  and  the  grain 

was  hurled  around  the  interior  and  did  not  bank  against  itself. 
An  elevator  in  the  neighborhood  of  New  York,  until 
recently,  had  been  dumping  their  dirt  into  the  harbor.  The 
plant  recently  changed  superintendents.  The  new  superin- 
tendent now  gathers  the  dust  and  fine  particles  of  grain  and 
separates  them,  although  he  does  not  sell  the  fine  dust,  he  is 
selling  the  fine  grain  and  says  he  is  able  to  get  top  notch 
prices  for  it.  There  is  a  concern  in  Baltimore  that  is  getting 
$11  a  ton  for  their  grain  dust. 

Dr.  DUVEL — Other  people  mix  a  little  molasses  with  it 
and  get  $40  a  ton. 

Mr.  BATES — The  attraction  between  this  crowd  of  men 
and  dust  is  something  I  can't  break  down.  We  are  supposed 
to  be  discussing  grain  handling  problems  but  you  always 
seem  to  find  something  to  say  about  dust. 

I  remember  an  incident  that  occurred  in  New  Orleans  where 
weevil v  wheat  was  being  unloaded  at  the  public  elevator  by 
a  suction  system  and  strange  to  say  when  the  wheat  was  de- 
livered there  were  no  weevils  in  it  and  though  they  v 
sure  that  weevils  were  going  into  the  elevator  pipe  none  v. 
coming  out.  Finally  by  microscopic  analysis  they  found 
fine  particles  of  the  weevils'  anatomy  in  the  dust.  The  weevils 
were  being  crushed  by  the  impact  of  the  flying  grain  which 
shows  another  conditioning  effect  of  this  type  of  elevator. 

"RELATION    OF    ASPIRATING    SYSTEMS    IX    GRAIN 
ELEVATi  >RS  TO  DUST  EXPL<  >SI<  >NS.  ' 

By  \V.  B.  Lind. 

What  i-  .in  aspirating  system  in  a  grain  elevator?  It 
system  of  dust  collectors  and  galvanized  steel  piping,  by  which 
the  dust  is  taken  from  the  elevator  boots,  garners  or  sca!<  s,  floor 
sweeps  and  the  various  cleaning  machines,  and  delivered  auto- 
matically to  the  boiler  furnaces,  as  fuel,  without  the  l<»sv  <»i'  an) 
grain,  thereby  keeping  the  elevator  clean,  utilizing  the  dust, 
ducing  the  insurance  rate,  and  preventing  dust  explosions. 

127 


The  Principle  of  Dust  Collecting. 

The  separation  of  dust  from  the  air  by  the  revolving  move- 
ment of  the  air,  and  throwing  the  dust  out  of  the  revolving 
current  because  of  its  greater  specific  gravity,  is  a  well-known 
principle,  and  is  the  method  chiefly  used  in  dust  collecting  systems 
operating  in  grain  elevators. 

1.  To  keep  a  grain  elevator  clean  is  a  problem  that  worries 
the  elevator  man,  and  a  dust  collecting  system  solves  this  problem 
in  a  most  satisfactory  way.  However,  its  efficiency  depends 
entirely  upon  its  installation.  The  amount  of  work  it  has  to  do 
varies  and  is  determined  by  the  number  of  points  from  which 
connections  are  to  be  made,  and  unless  all  tributary  and  main 
trunks  are,  as  to  size,  in  unison  with  the  size  of  fan  and  amount 
of  work  to  be  done,  the  system  becomes  useless.  It  is,  therefore, 
very  necessary  to  get  the  best  results,  that  a  dust  collecting 
system  be  properly  planned  and  installed  with  a  view  to  the  work 
to  be  done  and  the  conditions  in  each  case. 

2.  Points  of  application  in  the  minds  of  those  familiar  with 
aspirating  systems  as  used  in  elevators  differ  in  a  great  number 
of  cases,  as  it  must  be  remembered  that  nothing  of  any  value 
is  permitted  to  be  removed,  and  it  has  been  demonstrated  that 
points  where  aspirating  systems  could  do  the  most  good  were 
at  points  that  would  not  meet  with  the  approval  of  various  state 
and  warehouse  commissions.  It  being  their  contention  that 
some  of  the  principal  from  which  the  dust  was  to  be  removed 
would  also  be  carried  away,  thereby  developing  a  loss  greater 
than  would  be  the  good  derived  by  eliminating  hazards  brought 
on  by  dust  accumulations.  There  is  present,  however,  a  differ- 
ence  of  opinion  in  this  particular  phase  of  the  question,  as  I 
have  been  advised  in  numerous  instances  by  superintendents  of 
different  elevators  in  the  Northwest  that  the  amount  of  principal, 
should  any  he  removed,  is  of  minor  consequence.  Not  enough 
it"  any  would  he  losl  to  make  a  material  difference,  and  that 
between  the  loss,  if  any,  and  the  dangers  that  would  he  present 
from  the  dust  hazard,  the  latter  is  by  far  of  a  greater  im- 
portance. 

3.  Where   aspirating    systems    have    been   applied   at    such 

point-  a-  air  considered  by  a  warehouse  commission  and  state 
weighers  a-  a  point  from  which  a  loss  may  develop,  the  removal 
of  such  systems  from  that  particular  point  or  points  was  ordered 
and   as  a  consequence  there  are  a   number  of   elevators   that  are 

not  operating  their  aspirating  systems,  being  forced  to  abandon 

128 


them.  Consequently  the  elevator  becomes  easy  prey  to  dust, 
and  the  hazard  is  therefore  as  dangerous  as  is  the  case  in  an 
elevator  without  a  dust  collecting  system. 

4.  In  order  to  get  the  best  results  from  an  aspirating  system 
it  must  be  seen  to  regularly.  Very  often  connections  become 
separated,  main  trunks  and  tributaries  by  some  means  are  punc- 
tured, this  causes  air  to  escape  and  also  permits  dust  to  escape, 
the  latter  settling  about  plant  again.  The  loss  of  air  under  these 
conditions  is  of  much  importance.  If  there  is  not  sufficient  air 
pressure  behind  the  dust  in  main  trunks  and  tributaries,  dust 
will  then  settle  throughout  the  entire  trunking  systems.  Should 
this  condition  exist  and  some  form  of  ignition  develop  within 
aspirating  system,  and  enough  of  this  dust  brought  to  suspension, 
disastrous  results  would  be  sure  to  follow.  Propagation  would 
be  very  rapid  and  would  effect  entire  trunk  line,  resulting  in 
perhaps  loss  of  lives,  vast  property  damage  and  loss  of   food. 

5.  It  is  interesting  to  know,  even  though  most  elevator- 
are  equipped  with  dust  collecting  systems  they  are  not  always 
as  free  from  dust  as  are  some  plants  that  have  no  aspirating 
equipment.  There  are  several  reasons  for  such  conditions,  first, 
application  of  systems  at  improper  points;  second,  system  nol 
in  accordance  with  equipment  it  is  to  serve,  little  attention  per- 
haps having  been  given  to  trunk  size,  fan  size,  speed  of  same, 
distance  dust  must  be  carried  and  elbowing;  third,  lack  of  inter- 
est by  superintendent  and  help  about  a  plant  in  hazards  arising 
from  dust  accumulation. 

6.  In  bringing  out  more  clearly  this  latter  statement,  I  can 
cite  instances  where  aspirating  systems  are  installed  but  not 
regularly  in  use,  as  a  consequence  dust  is  in  evidence  throughout 
plant  in  considerable  quantity.  This  would  not  be  the  case  had 
collectors  been  in  operation.  I  have  seen  dust  in  piles  about  the 
floors  of  elevators;  a  floor  pick-up  trunk  would  be  close  by  and 
a  few  strokes  from  a  broom  would  bring  this  dust  pile  to  intake 
opening  of  pick-up  trunk  and  by  applying  power  to  fan  same 
could  be  removed  very  rapidly:  but.  instead  of  removing  at  once, 
it  would  remain  for  three  or  four  days  more.     In  the  meantime, 

that  same  pile  of  dust  may  hi-  the  caUSC  of  total  plant  destruction, 

life  and  fond      fust  such  conditions  demonstrate  most   forcibly 

the  necessity  of  daily  dust   removal  after  each  da\  's  run. 

7.     All   grain    elevators,    whether   equipped    with    aspirating 
systems  or  not,  should  have  enough  help  sweeping  regular! 
insure  dust  accumulation  removal  from  ; 


to  dust  collecting  equipment,  such  as  spout  tops,  bin  edge  tops, 
ledges,  underneath  belt  conveyors,  and  any  other  parts  impossible 
to  reach  with  mechanical  collecting  equipment  necessary  to  func- 
tion properly. 

In  conclusion,  will  say  clean  elevators:  (1)  Reduce  the  lire 
risk;  (2)  Give  better  working  conditions  for  the  employees; 
(3)  Prevent  dust  explosions;  (4)  Reduce  the  possibility  of  in- 
jury to  person  and  property,  and  liability  to  damage  suits;  (5) 
Save  that  which  it  is  impossible  for  the  human  body  to  exist 
without,  Food. 

System  of  Indirect  Suction. 

We  have  what  is  known  as  (and  same  is  now  being  installed 
in  several  elevators  in  Minneapolis),  an  Indirect  System  of 
Suction.     Some  of  you  are  familiar  with  this  I,  presume. 

This  system  consists  of  the  building  of  a  trunk  line  of  wood 
or  galvanized  iron  on  outside  of  garner  wall,  with  intake  opening 
connecting  at  top  of  hopper  scale  and  outlet  opening  from  roof 
of  garner  into  an  indirect  trunk  line  to  a  main  trunk  leading  into 
a  fan.  The  idea  is  that  when  feed  gates  of  garner  are  opened 
and  grain  drops  into  hopper  scale,  the  air  is  forced  up  and 
carries  dust  with  it.  The  dust  is  led  through  inside  top  of  garner 
to  an  opening  in  garner  roof  and  then  to  a  trunk  connected 
indirectly  with  a  fan  as  above  described.  Another  connection 
can  also  be  used  that  leads  to  an  opening  to  down  leg. 

The  object  is,  as  relating  to  down  leg  connection,  by  the 
suction  created  by  belt  cups,  to  draw  the  dust  with  aid  of  air 
1  herein  created  to  bottom  of  leg  or  boot,  and  when  it  gets  into 
the  boot,  there  is  another  independent  connection  which  extends 
over  the  outside  of  both  sides  of  boot  and  is  connected  to  a 
trunk  between  legs  which  is  also  connected  to  a  fan  that  draws 
this  dust   into  cyclone  inside  or  out. 

This  system  is  called  indirect  because  it  is  not  directed  on 
the  grain  proper.  With  reference  to  connection  on  garner  head 
or  roof,  it  has  a  short  trunk  extending  up  possibly  6  or  8  inches. 

It  is  4  feet  between  the  wheat  line  and  roof  of  garner.  The 
object  is  to  extend  this  connection  as  far  away  from  the  grain  as 
vmi  can.  It  is  then  disconnected,  leaving  a  space  of  four  or  five 
inches;  a  bell  shaped  Imod  with  a  larger  circumference  than  the 
trunk,  is  attached  over  this  short   trunk. 

There    is   an    installation    of   this   type    in    the   Crescent    "II" 

Elevator    in     Minneapolis,    hut    the    method    of    installation    just 

ribed    was    not    strictly    adhered    to;    instead    the    hood    was 

130 


brought  down  flush  with  garner  roof.  This  connection  is  much 
more  effective  but  when  it  was  found  they  had  made  a  direct 
connection  they  were  ordered  to  remove  same  and  went  back  to 
the  plan  referred  to.  In  applying  fan  to  trunk  line  it  was  found 
very  ineffective;  because  of  the  distance  between  short  trunk. 
and  hood  being  open  dust  would  escape,  also  air,  and  the  dust 
would  then  settle  on  roof  of  garner  and  also  on  garner  floor. 
It  is  for  this  reason  that  they  have  stopped  any  further  con- 
sideration of  that  system  in  the  balance  of  their  garners.  They 
hope  to  determine  very  soon  the  advisability  of  bringing  funnel 
or  hood  flush  with  roof  of  garners  by  taking  the  matter  up  with 
the  state  officials.  If  this  can  be  done  the  system  will  be  installed 
on  all  garners,  but  if  not,  then  no  further  consideration  will  be 
given  it  by  the  Crescent  "  H  "  Elevator. 

I  don't  know  whether  it  will  be  successful  or  not.  The  weigh- 
master  advised  that  it  would  not  be  unless  same  could  be  built 
flush  with  garner  roof  and  eliminate  the  open  space  between  short 
trunk  from  garner  roof  to  funnel  or  hood.  It  has  been  tried 
both  ways  in  this  plant  and  found  to  work  very  well  as^  here 
described,  and  no  loss  of  any  grain  was  noticed. 

The  system  not  being  generalized,  I  believe,  this  is  as  much  as 
is  known  of  it  at  present. 

Mr.  BATES — Is  the  method  devised  to  remove  as  little  dust 
as  possible  from  the  grain? 

Mr.  LIND — Yes,  and  in  its  present  form  very  little  dust  will 
be  removed. 

Mr.  PRICE — Is  it  a  case  of  removing  as  much  as  you  can 
without  removing  very  much  ? 

Mr.  REED — It  looks  to  me  that  if  they  ever  do  have  an 
explosion  in  a  system  of  that  nature  they  are  going  to  have  a  real 
explosion.  More  dust  IS  being  added  all  the  time  and  there  is 
no  chance  for  any  of  it  to  escape.  There  would  be  every  chance 
possible  for  flame  propagation. 

Mr.  PRICE — We  feel  that  the  various  State  Commissions 
have  certain  grounds  for  the  position  they  take  regarding  the 
use  of  aspirating  systems.  An  official  in  a  Western  state  has 
been  impressed  as  a  result  of  a  recent  explosion  in  that  section. 
We  had  the  same  experience  in  Canada.  It  happened  in  the 
explosion  at  Tort  Colborne  that  the  aspirating  system  wa 
operating,  because  it-  use  had  been  prohibited.  <  Hit  feeling 
is  just  the  sana-  as  11  always  has  been,  and  this  is  a  question 

131 


which  should  be  gone  into  at  the  earliest  opportunity  and  settled. 
We  should  work  out  a  code  regarding  the  points  at  which 
aspiration  can  be  applied,  together  with  size  of  fans,  points  of 
suction,  etc.,  necessary.  I  am  a  little  afraid  that  the  indirect 
suction  method  designed  is  not  going  to  accomplish  what  we 
have  in  mind.  I  think  it  is  way  ahead  of  what  the  commissioners 
have  considered  up  to  this  time  and  some  of  the  state  officials 
have  changed  their  ideas.  I  had  a  conference  with  some  of  these 
men  recently  in  Chicago.  I  found  that  they  were  very  free  to 
discuss  the  matter  but  were  strong  in  their  position.  They  cited^ 
cases  where  the  privilege  had  been  abused  and  they  are  perfectly 
willing,  I  think,  to  work  out  some  arrangement  whereby  this 
entire  matter  can  be  handled  if  it  is  to  be  on  a  basis  of  definite 
control. 

Mr!  HELMKAMP— One  of  the  officials  I  have  met,  I  think, 
wants  to  see  this  hazard  reduced  as  much  as  possible.  He  is  in 
favor  of  suction  of  some  kind  being  applied.  He  asked  if  it  was 
possible  to  put  a  glass  tube  in  whereby  the  weighmaster  could 
see  \jfizt  none  of  the  grain  was  being  sucked  up  at  any  time.  The 
suction  stream  could  be  observed  by  the  weighmaster. 

Dr.  BAILEY — In  fairness  to  the  Minnesota  Commission  I 
might  state  that  I  believe  the  commission  itself  is  favorable  to 
the  idea  of  installing  proper  dust  collecting  systems  in  the  eleva- 
tors, but  they  have  been  forced  to  bow  to  the  weight  of  public 
opinion  in  the  matter,  which  a  few  years  ago  was  thoroughly 
aroused  by  certain  situations,  which  more  or  less  justified  sus- 
picion. If  the  Department  can  evolve  a  system  or  code  which 
involves  such  mechanical  installations  as  will  make  impossible 
improper  manipulation  by  the  elevator  operators,  I  believe  the 
Commission  will  be  prepared  to  indorse  it  and  insure  its  more 
or  less  universal  adoption  in  the  elevators  of  Minnesota. 

Mr.  BATES— We  have  to  realize  that  we  are  living  in  a 
political  organization  where  the  majority  usually  have  their 
way.  The  sooner  we  realize  that  we  can  just  work  our  heads 
off  so  far  as  technical  work  is  concerned  if  we  don't  get  the 
support  <»f  the  public,  our  work  will  count  for  little.     It  seems 

to    me    that    the    thing    needed    more    than    anything   else    is,   you 

might  eall  it.  propaganda,  to  show  the  value  Mt  dust;  to  prove 
to  these  people  who  are  taking  Mich  a  nan«»w  view  of  the 
situation  that  the\  will  actually  receive  more  money  by  re- 
moving their  dust  and  selling  it  as  dust,  and  point  to  the  other 

advantages  as  well.    I  believe  that  if  we  can  make  the  elevator 

132 


man  and  the  little  grain  dealer  see  the  advantage  of  this  the 
big  man  is  bound  to  come  around.  All  political  activity,  I 
believe,  comes  from  the  masses,  or  should.  We  ought  to  give 
more  publicity  to  the  work  we  are  doing  in  dust  collecting  and 
force  these  operators  to  permit  aspiration  as  apparently  they 
are  willing  to  permit  dust  collection  if  the  .people  want  it.  The 
danger  of  removing  grain  with  the  dust,  is,  I  believe  most 
everyone  will  realize,  a  purely  imaginary  difficulty.  We  find  in 
thresher  work,  that  a  fan  to  do  fairly  good  cleaning  with  an 
aspirator  requires  a  very  high  velocity  in  order  to  lift  the 
heavier  particles  from  the  grain.  A  glass  peep  hole  in  a 
suction  tube  would  be  of  no  use,  for  of  course,  the  grain  is 
going  pretty  fast.  Usually  when  it  gets  a  start  you  wouldn't 
have  an  opportunity  to  observe  whether  it  was  a  kernel  of 
grain  or  something  else  when  it  goes  up  through  in  the  glass 
tube,  or  window. 

Mr.  PRICE — 1  just  want  to  take  a  minute  to  clear  up  our 
position.  I  think  we  enjoy  a  position  of  distinct  advantage 
over  the  State  Commissions  as  far  as  publicity  is  concerned 
and  we  might  abuse  that  advantage.  The  State  Commissions 
have  not  resented  what  we  have  said  in  public  but  they  told 
me  that  it  has  hurt  them  just  a  little  because  we  have  come 
out  definitely  and  said  that  we  might  prevent  these  explosions 
if  aspiration  was  applied  and  asked  me  upon  what  foundation 
that  statement  was  based.  Of  course,  to  answer  a  question 
of  that  kind  before  a  commission  is  difficult.  It  is  assuming 
that  we  are  going  to  take  out  a  certain  amount  of  dust  that 
might  settle  and  be  propagated  from  a  primary  to  a  secondary 
explosion.  My  own  Feeling  is  that  beyond  question  aspiration 
should  be  applied,  but  we  have  got  to  be  just  a  little  cautious 
until  we  can  work  it  out  pretty  definitely. 

Mr.   BATES — T  am  sure   Mr.   Price  has  proved  himself  a 

diplomat  many  times.  It  will  be  well  to  take  his  remarks 
with  a  great   deal  of  Consideration.      The  next   paper   is  by    Mr. 

Helmkamp   relative   t<>  a   novel   or  new    method,  or   proci 
which  he  has  run  across  in  his  wanderings. 

A  SYSTEM  <  >F  A  Ik  PURIFICATK  'X  IX  FL<  >UR  MILLS 

By    II.     I.     M  I   I    M  K  A  M  I'. 

In    the    southwest    recentl}     it    was    my    pleasure    to    inS] 
a  system  of  air  purification   which   was  installed  in  one  ot"  the 

flour  mills  in  that  section.     The  process  is  a  system  whereb) 

133 


washed  air  is  provided  to  the  purifiers,  reels  and  rolls,  through- 
out the  manufacture  of  the  flour.  A  machine  washing 
25,000  cu.  ft.  of  air  per  minute  is  used.  This  machine  is  located 
on  the  second  floor. 

The  air  is  washed  in  this  air-washing  machine  and  by 
means  of  baffle  plates  the  moisture  is  precipitated  out.  By 
means  of  small  sprays  sufficient  moisture  is  then  added  to  the 
air.  By  means  of  large  ducts  and  pipes  the  washed  air  is 
then  furnished  to  all  the  purifiers,  reels  and  rolls.  The  ma- 
chines to  which  this  air  is  furnished  are  made  practically  air 
tight  so  that  only  this  washed  air  comes  in  contact  with  the  stock. 

Some  of  the  benefits  that  result  from  this  installation  are 
as  follows : 

First:  Since  only  pure,  clean,  washed  air  comes  in  con- 
tact with  the  stock,  the  stock  is  kept  free  from  any  dirt  and 
dust  that  might  ordinarily  be  in  the  air  of  a  flour  mill.  Thus 
a  cleaner  product  is  made. 

Second :  The  air  throughout  the  mill  is  cleaner  inasmuch 
as  it  is  being  continually  washed.  At  the  time  of  my  visit 
the  air  seemed  to  be  exceptionally  pure  and  free  from  dust. 
Thus  the  danger  of  dust  explosion  is  practically  eliminated 
and  the  working  conditions  made  much  healthier  for  the 
workmen. 

Third :  The  time  for  tempering  the  grain  is  reduced  to 
about  six  hours.  The  moist  air  keeps  the  stock  uniformly 
moistened  throughout  all  the  mill  streams.  This  reduces  the 
number  of  tempering  bins. 

Fourth:  The  air  in  the  mill  is  kept  cooler  at  all  times 
than  the  machines,  which  is  necessary  for  good  milling. 

Fifth :  The  life  of  purifier  and  bolting  cloths  are  lengthened. 
This  is  because  this  blue-blackish  dust  never  comes  in  con  tart 
with  the  cloth. 

Sixth.  Ash  in  the  product  is  reduced  because  the  stock 
is  moist  at  the  tail  of  the  mill  and  consequently  pulverizing  is 
prevented.  In  the  ordinary  process  of  milling  moisture  is 
given  up  so  that  the  finished  product  has  possibly  three  per 
cent,  less  moisture  than  the  wheat  entering  t he  mill.  This 
loss  IS  known  as  invisible  loss.  So  it  is  evident  that  the  stock 
at  the  tail  of  the  mill  is  quite  dry  and  naturally  pulverized 

more  readily.  By  this  process  the  stock  is  kept  as  near  as 
possible  to  the  same  per  cent.  <>!"  moisture  and  thus  pulverizing 

134 


of  stock  at  the  tail  of  the  mill  is  reduced  and  hence  the  ash 
is  rduced.  In  addition  to  this  it  is  evident  that  the  invisible 
loss  in  milling  is  less. 

Below  is  the  average  of  a  large  number  of  laboratory  tests 
made  before  and  after  the  process  was  installed. 


1 

Moisture  of 

wheat  entering 

mill. 

Per 

Cent. 

Moisture  of 

wheat  on 

rolls. 

Per 

Cent. 

Moisture 

of 

Product. 

Per 

Cent. 

Moisture  Loss, 
difference 
wheat  over 

rolls  product. 
Per  Cent. 

Ash. 

Straight 

Grade. 

Per 

Cent. 

Before 
After 

I 

9.9 
11.6 

15.6 
14 

12.8 
13 

2.8 

1 

.49 
.43 

In  conclusion,  I  might  say  that,  first,  a  purer  and  cleaner 
product  is  made  and,  second,  the  air  throughout  the  mill  is 
kept  clean  and  practically  free  from  dust,  thus  reducing  the 
dust  explosion  hazard. 

Mr.  BATES — A  very  interesting  paper.  I  don't  know  how 
well  we  are  equipped  to  discuss  it.  but  will  be  glad  to  hear 
any  remarks. 

Mr.  PRICE — I  think  this  is  an  elegant  opportunity  for  our 

flour  milling  men  to  discuss  this.  Mr.  Helmkamp  thinks  it  is 
effective  in  explosion  prevention.  This  is  the  first  time  it  has 
been  brought  to  our  attention  .  We  would  like  very  much  to 
have  your  opinions. 

Dr.  BAILEY — This  is  a  sort  of  modification  of  an  English 
process  known  as  the  Humphreys  Process  in  which  they  intro- 
duce the  water  right  into  the  machines  themselves.  Now, 
from  the  description  given  by  Mr.  Helmkamp,  1  assume  that 
this  air  treating  device,  in  addition  to  washing  the  impurities 
OUl  of  the  air  also  humidities  it. 

Mr.  HELMKAMP— The  air  is  taken  in  and  washed,  the 
excess  moisture  precipitated  out.  By  means  of  sprays  moisture 
is  then  added  to  the  air. 

Mr.  BAILEY  It*  the  air  is  washed,  even  though  an  effort 
is  made  to  precipitate  out  the  water  globules,  it  would  be  pretty 

well  saturated  with  moisture.      From  my  knowledge  of  the  USC 

similar  appliances  in  the  milling  industry  I  might  suggest  that 
humidifying  the  air,  rather  than  removing  the  impurities,  was 

the  object    and   what    the   inventor   was   really   aiming  at    was  the 

135 


prevention  of  invisible  loss  and  also  incidentally,  at  the  same  time, 
keeping  down  the  ash  content.  Invisible  loss  is  a  big  thing  and 
purification  of  the  air  is,  to  my  mind,  largely  camouflage. 

Mr.  HELMKAMP — Only  pure  air  enters  the  purifiers,  which 
are  made  air  tight.  Only  washed  air  comes  in  contact  with  the 
grain. 

Mr.  PRICE — I  would  like  to  ask  Mr.  Bailey,  by  reducing  the 
invisible  loss,  do  you  mean  that  this  is  an  opportunity  to  add 
enough  water  to  overcome  this? 

Mr.  BAILEY — Enough  water  to  offset  that  which  would  be 
lost  in  evaporation. 

Mr.  PRICE — We  had  that  same  question  come  up  at  Chicago. 
Occasionally  we  suggest  something  which  apparently  conflicts 
with  the  law.  In  the  grinding  of  oat  hulls,  we  thought  by  restor- 
ing the  moisture  to  the  original  amount  we  might  reduce  the 
danger  of  dust  explosions.  The  difficulty  has  been  to  tell  where 
to  stop. 

Mr.  BROWN — It  occurs  to  me  that  if  air  can  be  used  in  this 
installation  why  not  use  an  inert  gas  and  remove  all  danger  of 
explosion? 

Dr.  BAILEY — It  would  require  an  enormous  quantity 
assuming  you  could  keep  it  all  there  after  you  once  put  it  there. 
May  I  ask,  Mr.  Brown,  in  the  consideration  of  the  use  of  inert 
gas,  I  presume  you  propose  taking  it  from  the  smoke  stack  and 
purifying  it  in  some  way. 

Mr.  BROWN — Yes,  it  would  be  taken  from  the  stack  and 
enough  added  to  the  air  to  reduce  the  oxygen  content  to  proba- 
bly not  over  15  per  cent. 

Dr.  BAILEY — There  is  always  an  element  of  danger  in 
taking  gas  from  the  smoke  stack  owing  to  the  big  percentages  of 
S( ).,  and  S( ).,.  Unless  they  are  completely  removed  their  sub- 
sequent introduction  into  the  flour  system  would  be  very 
dangerous. 

Dr.  I'.ROWN — That  is  a  rather  interesting  question  t<>  me 
because  we  started  this  work  on  inert  gas  3J4  to  4  years  ago 
In  1917,  at  one  of  the  large  industrial  plants,  we  were  doing 
-•Mm-   work   on   thai   and   naturally   ran   into   the  objection   which 

Dr.  Bailey  has  raised.  In  order  to  overcome  this,  we  arranged 
to  pump  flue  gases  into  a  barrel  <>r  box  in  which  Hour  was 

136 


being  continually  agitated  by  tumbling.  Taking  first  ordinary 
flue  gas,  which  had  been  thoroughly  washed,  and  then  gradually 
running  up  the  impurities  until  they  were  very  high,  on  account 
of  incomplete  combustion  of  the  coal,  and  the  gases  not  being 
washed,  not  until  we  could  actually  observe  by  the  naked  eye 
impurities  in  the  flour  was  there  any  very  noticeable  effect. 
According  to  tests  made  at  the  Government  Laboratory  at 
Chicago  and  further  tests,  including  baking  tests,  made  at  the 
Department  Laboratory  in  Washington,  not  until  we  could 
actually  smell  in  the  flour,  or  coming  from  the  flour  a  distinct 
odor  of  flue  gases  and  could  observe  in  them  the  Foreign  particles 
of  soot,  did  we  find  any  deleterious  effect. 

Dr.  BAILEY — Was  the  effect  judged  by  the  size  of  loaf  or 

was  it  a  test  of  the  flavor? 

Dr.  BROWN — Both  the  sponging  test  and  several  others 
were  run.  In  fact,  no  effect  was  noticeable  until  the  flour  had 
actually  been  in  this  atmosphere  of  gas,  agitated  continually,  for 
about  2y2  to  3  hours,  which  is  considerably  longer  than  it  would 
be  in  the  presence  of  any  inert  gas  in  passing  through  an  ordinar) 
milling  process  where  inert  gas  might  be  tised. 

Mr.  BAILEY — That  sounds  like  pretty  conclusive  evidence. 
We  are  always  concerned  by  the  presence  of  S( ).,.  It  is  very 
antagonistic  to  yeasl  and  has  a  harmful  effect  on  the  gluten  of 
flour  where  greater  quantities  of  S<  ).,  might  not  affect  other 
cereals  at  all. 

As  I  recall  Mr.  Helmkamp's  description  of  this  process,  this 
air  is  used  principally  in  machines  where  we  don't  ordinarily 
regard  the  explosion  hazards  as  very  high.  So  the  use  of  inert 
gas  wouldn't  be  as  significant  as  in  some  other  places.  Especially 
as  this  process  uses  humid  air  perhaps  the  danger  of  explosions 
is  more  remote  than  in  dryer  air. 

Mr.  HELMKAMP  The  principal  objection  is  that  it  makes 
added  trouble  for  the  miller  to  keep  the  thing  regulated  properly 
at  all  times. 

Mr.  PRICE  We  must  remember  that  the  flour  milling 
Industry  is  not  experiencing  the  number  of  explosions  that  the 
other  industries  are.  the  grain  elevators  for  instance,  and  starch 
and  sometimes  sugar.  The  inert  gas  theory  has  not  been 
developed  with  the  flour  industry  particularly  in  mind.  \\ 
that  it  might  be  applied  to  the  grinding  of  oaf  hulls,  but  it  hasn't 
been  given  serious  consideration  in  connection  with  flour  milling. 

137 


Mr.  BATES — We  now  come  to  the  paper  of  Dr.  H.  H. 
Brown  on  the  results  and  impressions  in  dust  explosion  meetings. 
Probably  no  other  man  has  come  in  contact  with  the  general 
public  in  a  more  intimate  way  in  connection  with  this  work  over 
the  whole  country  than  has  Dr.  Brown.  He  has  been  the  main 
spokesman  at  a  great  many  meetings  throughout  the  entire 
country.  He,  being  a  chemist,  naturally  has  noticed  certain  reac- 
tions to  his  "  air  "  efforts  and  we  will  now  listen  to  his  summing 
up  of  how  the  public  received  the  explosion  of  dust  propaganda. 

RESULTS  AND  IMPRESSIONS  IN  DUST  EXPLOSION 

MEETINGS. 

By  Dr.  H.  H.  Brown. 

To  give  a  complete  discussion  of  this  subject  at  this  time 
seems  unnecessary,  since  most  of  you  are  familiar  with  the 
meetings  held  in  your  district,  and  know  about  many  of  the 
other  points  which  were  reached.  There  was  a  certain  similarity 
in  these  various  meetings,  and  yet  they  were  different.  So  per- 
haps a  brief  discussion  of  the  results  of  the  meetings  and  of 
the  impressions  which  I  received  in  them  will  be  of  benefit. 

As  you  know,  two  series  of  meetings  were  held.  The  first 
started  in  January  of  1918  and  continued  through  May  and  until 
early  June  of  that  year.  The  other  started  the  20th  of  last 
( October  and  the  last  meeting  was  held  on  the  30th  of  March  of 
this  present  year.  In  that  time  over  100  meetings  were  held.  In 
some  cases,  the  attendance  reached  eight  or  nine  hundred,  while 
in  others  only  about  a  dozen  or  fifteen  were  present.  But  in 
every  meeting  the  same  method  of  presentation  was  followed. 
While,  of  course,  we  appreciated  having  as  large  an  attendance  as 
possible,  we  always  felt  that  the  small  meetings  were  worth 
while  because  in  them  we  seemed  to  get  into  more  intimate  touch 
with  those  present.  This  may  have  been  due  to  the  fact  that  the 
men  felt  freer  to  enter  into  the  discussions  which  we  always  had 
following  the  presentation  of  the  subject. 

It  often  happened  that  at  points  where  we  did  not  anticipate 
having  a  very  good  meeting,  there  we  had  some  of  the  best.  Eor 
instance,  at  one  point  we  did  not  have  a  meeting  in  the  first  series 
because  we  felt  it  was  not  very  accessible  and  there  was  not  the 
interest  apparent  a-  at  some  places,  and  the  milling  capacity  was 
not  large.  This  point  was  reached  in  the  second  series.  Arrange- 
ments were  supposed  to  have  been  made  in  advance,  and  while 
on  arrival  there  was  not  mneli  that   I  could  see  to  be  done,  excepl 

138 


get  my  own  equipment  ready,  still  there  did  not  seem  to  have 
been  much  interest  aroused.  But  when  it  came  time  for  the 
meeting,  the  men  began  to  file  in,  first  one  at  a  time,  then  by  twos 
and  threes,  and  finally  a  dozen  or  more  at  a  time,  until  fully  a 
hundred  were  present.  It  developed  to  be  one  of  the  liveliest 
and  most  interesting  meetings  which  was  held. 

One  of  the  most  satisfying  things  in  the  two  different  series 
of  meetings  was  the  increased  interest  shown  in  the  second  meet- 
ing. For  instance,  at  one  point  only  a  few  over  two  hundred 
attended  the  first  meeting,  and  many  did  not  stay  for  the  dis- 
cussion which  lasted  less  than  half  an  hour ;  but  over  four 
hundred  attended  the  second  meeting  and  most  of  them  stayed 
for  the  discussion  which  lasted  fully  an  hour,  and  after  that  sev- 
eral stayed  to  go  over  some  particular  questions  of  immediate 
interest.  A  few  figures  may  well  be  used  to  show  how  the 
interest  increased.  In  1918  we  visited  about  seventy  different 
points  and  had  an  attendance,  as  shown  by  signcd-cards.  of  .\172. 
At  thirty-eight  different  points  this  year  we  had  2,637  signed 
cards.  Cards  were  not  used  in  four  other  meetings  this  year. 
At  these  forty-two  meetings  there  was  an  estimated  attendance 
of  about  6,300  people.  In  1918  the  estimate  was  about  5,000  for 
all  of  those  points.  I  feel  that  the  increased  interest  which  has 
been  shown  in  this  work  during  the  past  year  has  been  largely 
due  to  the  activities  of  the  Grain  Corporation  and  to  the  fine 
co-operation  that  was  given  by  the  Zone  Agents,  to  the  publicity 
given  through  them  and  the  interest  which  they  aroused. 

The  National  Hoard  of  Fire  Underwriters  deserve  a  great 
deal  of  credit  for  what  they  did  in  helping  to  make  the  meetings 
so  successful  Through  their  activity,  large  numbers  of  insurance 
men  and  lire  inspectors  attended.  These  men  often  said  that 
after  listening  to  what  1  had  t<>  say  and  after  seeing  the  pictures 

and  the  demonstrations,  that  they  knew  more  what  to  look  for 
when  inspecting  a  plant,  and  that  they  had  some  argument  which 
they  could  utilize  in  speaking  with  the  men  in  the/rade  in  trying 

to  get  them  to  put  in  safety  precautions.  1  feel  that  they  air 
--in-  to  extend  the  work  and  carry  it  on  in  that  way. 

We  always  had  discussion  in  the  meetings.     Numerous  ques 

tions  were  asked.  1ml    I    think  that    we  learned  probably  a-  much 

if  not  more  from  side  discussion  after  the  meetings  were  over, 
at  least  a-  to  how  the  work  was  received.     For  instance,  a  man 
who  had  been  active  in  arranging  for  the  meeting  at    Dem 
told  me  alter  the  meeting  that  a  man  sitting  righl  behind  him 

spoke  to  his  friend  nearby  and  said:   "  Well.  I  did  not  have  an) 

18 


realization  of  this  thing;  believe  me,  I  am  going  home  and  get 
my  broom  busy."  At  a  meeting  at  Fort  Worth,  Texas,  a  man 
said :  "  I  often  go  down  into  the  basement  to  clear  a  choke  or 
for  some  other  reason.  I  have  electric  lights  down  there,  but 
sometimes  I  forget  to  turn  on  the  switch,  and  so  I  just  strike  a 
match ;  you  can  bet  I  will  never  do  it  again." 

Of  these  recent  explosions,  the  one  which  occurred  in  Kansas 
City  probably  created  the  most  interest.  This  may  have  been 
because  it  was  the  most  recent  and  on  account  of  the  large  loss  of 
life.  Many  false  impressions  and  opinions  had  been  obtained 
which  it  was  necessary  to  correct.  For  instance,  at  one  point, 
the  report  was  current  that  the  explosion  had  been  caused  by 
one  of  our  men  giving  a  demonstration.  This  little  explosion 
was  supposed  to  have  started  the  larger  one.  It  was  necessary  to 
correct  this  report  before  a  place  could  be  secured  for  holding 
the  meeting,  because  they  were  afraid  of  our  destroying  the 
building. 

I  feel  that  the  general  impression  of  the  trade  is  largely  this : 
That  until  this  work  was  started,  until  this  campaign  was  put  on, 
they  had  no  realization  at  all  of  the  hazard,  the  inherent  hazard 
there  is  in  dust.  This  has  been  expressed  by  men  from  one  end 
of  the  country  to  the  other.  They  had  no  idea  of  the  damage 
that  could  be  done,  of  the  ease  with  which  the  dust  could  be 
ignited,  and  really  wondered,  as  do  we,  why  more  explosions  do 
not  occur.  The  large  number  of  inquiries  which  are  coming  in 
daily  is  a  very  good  indication  of  what  the  meetings  have  done 
and  of  the  amount  of  interest  that  was  aroused.  It  was  not 
possible  to  go  into  detail  on  the  various  questions  and  these  are 
being  sent  in  as  well  as  a  large  number  of  most  interesting  and 
unique  inquiries  and  suggestions.  Several  companies  have  asked 
where  vapor-proof  globes  could  be  obtained,  and  after  receiving 
the  information  have  installed  them  throughout  their  plants.  One 
of  the  most  frequent  inquiries  on  methods  of  prevention  has  been 
for  details  of  bow  to  eliminate  static  electricity.  These  are  only  a 
few  of  the  points  upon  which  we  are  asked  to  give  advice. 

You    may   he   interested    in    some   of    the   questions   that    were 

raised  at  the  meetings  in  various  sections  of  the  country  regarding 
the  different  phases  of  the  work.  I  >ne  of  the  things  probabl) 
brought  out  a-  much  as  anything  in  the  discussions  during  tin- 
recent  -nies  of  meetings  was  the  question  of  construction  o\ 
plants;  what  is  the  best  construction  to  he  used.  Naturally,  that 
came  up  as  a  result  of  the  explosions  which  have  occurred  these 

past     few    months    in    plants    constructed    Of    fireproof    material. 

140 


From  some  of  the  questions  asked  along  this  line  by  insurance 
representatives,  it  could  be  seen  that  the  insurance  interests  were 
gradually  coming  to  feel  that  they  must  increase  the  rate  of  in- 
surance on  grain,  and  increase  it  on  grain  stored  in  fireproof 
plants.  It  seems  to  me  that  that  is  one  thing  we  must  counteract. 
They  have  not  realized  the  fact  that  it  is  not  the  grain  that  is 
damaged,  but  that  it  is  the  plant.  Very  little  grain  has  been  lost 
in  any  of  these  explosions. 

It  was  only  natural  that  preventive  devices  should  have  been 
of  considerable  interest.  In  discussing  that  question,  men  would 
state  that  they  had  a  certain  type  of  installation  in  their  plant  and 
asked  our  opinion  of  it.  As  a  result  of  the  meetings  and  discis- 
sions, it  seems  to  me  that  one  of  the  big  fields  for  development 
in  cleaning  devices,  as  applied  to  mills  and  elevators,  is  in  a 
vacuum  dust  collecting  and  cleaning  system.  I  feel  that  the 
majority  of  the  plants  would  put  in  such  an  installation  and  do  it 
gladly-  There  is  not  one  of  these  operating  successfully  at  the 
present  time,  and  I  think  that  is  something  upon  which  wc  men 
who  are  going  out  might  do  well  to  put  a  little  time. 

The  points  which  were  discussed  in  the  meetings  varied  in 
different  sections  of  the  country.  For  instance,  in  the  Pacific 
Northwest,  where  considerable  work  has  been  done  on  the  <[iu- 
lion  of  static  electricity  in  threshing  machines,  and  in  the  South, 
where  we  studied  its  effect  in  cotton  gins,  it  was  only  natural 
that  much  of  the  discussion  should  be  on  the  causes  and  means 
of  prevention  of  static  electricity.  In  the  Northwest  and  up 
through  the  Dakotas  and  Montana,  they  were  very  much  inter- 
ested in  the  question  of  explosions  in  country  elevators.  At 
Great  Falls,  Montana,  where  we  had  two  meetings,  one  in  the 
Spring  of  1918  and  one  in  the  Fall  of  1919,  they  were  very  much 
interested  in  this  question,  and  at  each  of  these  meetings  we 
were  told  of  explosions  in  these  types  of  elevators.  When  a 
milling  center  was  reached,  the  questions  were  along  lines  of  pre 
vention  of  explosions  in  mills,  and  in  a  grain  handling  center,  the 
prevention  of  explosions  in  elevators  was  the  chief  topic  oi 
discussion. 

isiderable  interesl  was  shown  in  our  discussion  of  <  • 
sions  being  caused  1»\   sparks  struck  1>\   foreign  material  passing 
through  grinding  machines     At  almost  every  meeting  men  in  the 
audience  cited  .here  small  explosions  had  started   from 

such  causes,  and  these  brought  forth  some  very  interesting  dis 
cussions.     This  would  lead  to  the  question  of  preventing  the 
propagation  of  these  explosions  beyond  the  grinding  marl; 

141 


While  in  the  East  we  had  rather  been  working  toward  the  revolv- 
ing damper,  in  the  West  they  were  working  toward  the  use  of  a 
choke  conveyor  equipped  with  a  vent  between  the  choke  and  the 
machine.  Personally  I  feel  that  this  device  is  really  as  effective, 
if  not  more  effective,  than  the  revolving  damper. 

The  discussion  of  explosions  in  plants  other  than  cereal  plants, 
such  as  the  explosion  which  occurred  in  a  spice  plant  at  Cin- 
cinnati, brought  out  several  questions  as  to  what  types  of  dust 
will  explode.  In  Los  Angeles  I  was  asked  the  question  whether 
the  dust  that  the  housewife  sweeps  up  around  the  house  will 
explode,  and  what  was  the  danger  of  getting  too  much  dust  in 
the  home.  At  another  point  a  man  wanted  to  know  if  road  dust 
would  explode,  possibly  figuring  on  using  it  instead  of  gasoline. 

Carelessness  of  operation,  imperfect  equipment,  the  possible 
effect  of  weather,  of  humidity  and  of  temperature,  and  many 
other  questions,  came  in  for  their  share  in  the  discussion.  The 
question  of  collecting  the  dust  at  the  source,  at  the  point  of  origin, 
brought  out  a  great  deal  of  interesting  and  fruitful  discussion. 
An  interesting  case  was  found  in  Detroit  where  a  hood  had  been 
placed  over  the  grating  at  the  point  of  unloading  of  the  cars  to 
remove  the  dust  at  that  point  and  to  keep  the  unloading  station 
clean.  It  is  interesting  to  note  that  they  had  kept  track  of  the 
amount  of  dust  and  found  that  they  collected  about  eight  pounds 
for  every  thousand  bushels  of  grain.  Some  agreed  that  it  was 
the  best  thing  to  do  from  the  standpoint  of  preventing  explosions, 
while  others  could  not  see  beyond  what  seemed  to  be  a  real  or 
imaginary  monetary  loss.  In  practically  every  meeting  the  dis- 
cussions were  very  interesting  and  profitable,  and  much  valuable 
information  was  obtained  in  them. 

We  have  all  run  across  some  interesting  instances  of  small 
explosions  or  of  means  of  demonstration.  One  which  came  to  my 
attention  was  that  a  number  of  children  were  in  the  habit  of 
playing  on  a  dump  where  dust  had  been  thrown.  Some  of  the 
dust  was  smoldering  and  the  boys  would  take  cloth  bags  and  till 
them  with  dust  and  shake  them  over  the  smouldering  mass,  just  to 
see  the  flames  shoot  up.  One  of  the  boys  was  badly  burned  as  a 
result.  But  I  think  the  most  interesting  story  which  came  to  me 
was  told  by  a  man  in  Stockton.  California,  lie  had  worked  for 
some  time  in  lumber  camps,  and  when  he  saw  our  demonstration 
with   the   cheese  Cloth,   he   said:      "That    is   exactly    like   what    we 

used  to  do  to  get  rid  of  the  ilies  in  the  camp  kitchen.     Even 
though  we  had  screens,  sometimes  the  kitchen  would  get  so  full 

of  flies  that  the  rook   would   reach  into  the  barrel    for  a  handful 

142 


of  flour  and  throw  it  over  a  piece  of  burning  paper.  The  flame 
would  shoot  through  the  room  and  burn  the  wings  off  the  flies. 
Then  he  would  sweep  them  out."  They  called  it  "  shooting  the 
flies." 

The  expressions  of  appreciation  that  we  received  at  every 
point  throughout  the  country  were  really  very  gratifying.  I  think 
it  has  been  specially  so  in  this  last  series  of  meetings.  Many 
expressions  of  appreciation  were  received  from  the  milling  and 
grain  trade  and  insurance  interests  of  the  fact  that  the  Grain 
Corporation  saw  fit  to  continue  the  work  during  this  past  year 
and  to  extend  the  work  so  that  they  might  get  the  benefit  of  it. 
The  motion  pictures  that  we  had  this  year  made  a  profound  im- 
pression. When  we  showed  the  explosion  in  the  steel  gallery, 
and  especially  the  starch  explosion,  you  would  hear  throughout 
the  audience  sounds  of  surprise  and  wonderment  that  dust  could 
be  ignited  so  quickly.  When  they  saw  the  destruction  which 
resulted  from  explosions  in  the  plants,  and  were  told  of  some  of 
the  things  found  in  our  investigations,  as  for  instance,  in  the 
Cedar  Rapids  explosion,  that  a  child  sleeping  in  a  bed  half  a 
mile  away  from  the  plant  was  thrown  out  of  bed  and  killed,  they 
were  very  much  interested.    The  men  in  the  grain  interests  have 

•in  to  think  of  these  things  at  least,  and  I  feel  that  a  great 

I  of  good  has  been  accomplished. 

Mr.  MOORE — Any  important  explosions  in  the  last  six 
months  ? 

Dr.  BROWN — No,  not  in  elevators.  There  was  one  in  a  flour 
mill  in  Denver,  but  that  was  a  minor  explosion,  no  loss  of  life. 

ther  occurred  in  an  aluminum  plant  at  Manitowoc,  Wisconsin, 
where  six  girls  were  killed;  that  was  an  explosion  of  aluminum 
dust.     That  was  all. 

Mr.  BATES  -I  think  probably  the  present  paper  is  de- 
batable, but  I  will  ask  Mr.  Price  to  take  the  chair  in  my  pla 

Mr.    PRICE— You   have  just  heard   from    Dr.    Brown   with 
ird   to   the   splendid   co-operation    from   the   Vice-Presidents 
of  tin-  Grain  Corporation  and  you  also  have  had  contact  dii 

with  these  men  in  your  various  districts  in  connection  with  in- 
:tion  work.  I  know  we  all  feel  that  a  great  deal  of  the 
-ess  we  have  had.  I  dm-  to  the  co-operation 

tin-  ( irain  i  '<  irp< » rat  ion.   1  want  to  state  thai  this 
iperation  with  the  'irain  Corporation  has  made  it  possible 

for  the  Department  of  Agriculture  to  render  further  valuable 

143 


service  throughout  the  country.  Dr.  Brown  has  just  referred 
to  the  very  disastrous  explosion  at  Manitowoc,  Wisconsin, 
which  occurred  in  a  plant  manufacturing  aluminum  ware,  in 
which  six  girls  were  killed  and  several  others  badly  injured. 
This  is  the  first  case  where  we  have  had  girls  actually  killed 
in  a  dust  explosion.  It  was  my  pleasure  to  be  in  Madison  a 
few  weeks  ago  and  meet  the  Governor  of  Wisconsin  and  also 
the  members  of  the  Wisconsin  State  Industrial  Commission. 
A  number  of  the  Commission  had  been  to  our  meeting  at  Mil- 
waukee, which  Dr.  Brown  had  conducted  there,  and  had  heard 
a  great  deal  about  grain  dust  explosions.  The  commission 
had  its  engineers  go  to  Manitowoc  when  this  explosion 
occurred  and  conduct  a  thorough  investigation,  with  the  result 
that  the  U.  S.  Department  of  Agriculture  and  the  State  Com- 
mission are  co-operating  in  the  preparation  of  a  code  of  pre- 
vention, which  they  hope  will  help  to  prevent  a  recurrence  of 
explosions  of  this  kind  in  that  state ;  the  Industrial  Com- 
mission being  very  active  and  very  much  up-to-date  in  that 
particular  respect. 

Another  concrete  case  whereby  we  have  been  enabled  to 
help  in  this  manner  has  been  in  connection  with  the  thresher 
work  in  the  Pacific  Northwest.  When  the  thresher  explosions 
occurred  there  in  1914,  the  insurance  rates  were  taken  off  by 
Insurance  Companies  owing  to  the  extensive  loss  to  machinery 
and  grain  in  that  section — around  a  million  dollars  being  lost 

a  result.  Up  until  last  year  it  has  been  almost  prohibitive, 
that  is,  the  rates  being  so  high  that  insurance  could  not  be 
carried.  The  rate  as  it  now  stands  on  threshing  machines  is 
\\y2  per  cent,  or  $11.50  per  hundred.  But  at  a  recent  con- 
ference in  Seattle  with  State  Officials  and  the  Insurance  Com- 
pany interests  west  of  the  Rocky  Mountains,  representing 
some  300  companies,  it  was  agreed  that  it'  they  equipped  their 
machines  with  the  precautionary  measures  recommended  by 
the  Government,  that  the  Insurance  Companies  would  be  able 

to  reduce  the  rate  below  the  present  rate  of  $11.50.  We  are 
in  hopes  that  the)  will  finally  make  it  around  $4  <>r  $5. 
At  the  time  of  the  Kansas  City  explosion  we  lacked  a 
nite  policy  as  to  tlu-  recommendations  to  be  made  for  the 
removal  of  dangerous  conditions  in  mills  and  elevators.  At 
that  time  the  Grain  Corporation  decided  it  would  be  very 
advisable  to  work  out  a  definite  policy,  which  we  have  been 
following,  so  that  when  conditions  of  danger  were  found  by 

run  men,  the)    could  he  removed  Immediately.     You  will  recall 

144 


in  your  various  districts,  where  the  elevator  operators  did  not 
follow  out  your  recommendations,  you  would  call  the  matter 
to  the  attention  of  the  Zone  Agent  and  in  many  cases  he  would 
call  the  company  on  the  phone  and  have  the  condition  remedied 
almost  instantly.  As  I  mention  this  I  see  a  number  of  the  men 
smiling  as  they  are  thinking  about  particular  cases  in  which 
that  happened.  The  formulation  of  that  policy  rested  largely 
with  one  of  the  Vice-Presidents  here  in  New  York,  and  I  take 
pleasure  in  presenting  Mr.  Moore  to  you,  and  I  am  sure  we 
would  be  glad  to  hear  from  him  at  this  time. 

STATEMENT   BY   MR.  WATSON  S.   MOORE,   DIREC- 
TOR and  SECOND  VICE-PRESIDENT  U.  S. 
GRAIN   CORPORATION. 

Mr.  M<  M  >RE — Mr.  Price,  you,  of  course,  have  had  a  great 
interest  in  this  work.  Air.  Barnes  has  undoubtedly  explained 
to  you  just  the  basis  on  which  we  had  a  right  to  interest  our- 
selves in  it,  and  that  is  on  account  of  the  large  amount  of 
grain  and  flour  that  we  had  at  risk  which  would  justify  an 
appropriation  that  has  helped  to  carry  on  this  work.  I  cer- 
tainly congratulate  you  on  the  splendid  work  that  you  have 
accomplished.  I  did  not  understand  that  the  dust  explosion 
work  has  had  such  a  wide  range,  as  suggested  by  Dr.  Brown — 
even  getting  into  the  homes,  and  I  had  expected  him  to 
illustrate  how  it  was  possible  to  prevent  explosions  in  the 
domestic  circle.  But  you  alone  know  how  important  the  work 
is  which  you  have  done.  I  have  not  seen  the  piles  of  dust 
that  you  men  have  seen  on  entering  plain-;  1  have  not  seen 
the  conditions.  You  have  gone  in  there  and  you  have  probably 
wondered  that  an  explosion  had  not  occurred  before  then,  and 
you  know  just  what  was  removed,  and  you  know  something 
of  the  responsibility  of  the  people  you  have  seen,  men  who 
were  deadened  to  your  recommendations  absolutely  and  gave 
you  the  wooden  ear.  and  1  should  imagine  you  had  to  explain 
things  to  them,  and  then  by  your  demonstrations  were  able 
to  arouse  their  interest  and  finally  their  investigation  and  then 
the  adoption  of  your  suggestions. 

Now  with  reference  to  the  proposition  here  in   New  York, 
with  these  elevators  that  were  cleaned  up.     In  Minneapolis  they 
had  such  large  elevator  capacity  that  they  tore  down  a  1"' 
wooden  elevators  and  made  pianos  out  of  th<  never  knew 

before  where  music  came  from  in  the  grain  business,  but  here 
in  New  York  where  the  usual  elevator  capacity  is  only  five  and 

145 


a  quarter  million  bushels,  equal  to  one  large  elevator  in  Chicago, 
you  see  what  it  would  mean  to  cripple  the  already  inadequate 
storage,  by  putting  any  part  of  the  capacity  out  of  business.  If 
the  Erie  Elevator  or  the  West-Shore  Elevator  should  be  blown 
up  and  destroyed,  it  would  be  a  serious  thing;  it  would  curtail 
shipments  abroad;  it  would  hamper  transportation  and  it  would 
ultimately  seriously  affect  the  producer.  So  your  work  is  greater 
than  you  sometimes  might  imagine.  Then  during  the  war,  you 
had  an  advantage  because  it  was  a  period  of  responsibility  on 
the  part  of  everybody.  Men  felt  they  must  refrain  from  bad 
practices  and  be  more  careful  and  protect  property,  and  all  that 
sort  of  thing — a  patriotic  impulse  in  helping  to  win  the  war;  the 
employees  felt  they  had  some  responsibility  toward  a  successful 
termination  of  the  war.  Now  you  have  been  dealing  with  a 
reactionary  period,  among  men,  and  especially  among  laboring 
men  and  the  employed  men.  They  feel  they  are  not  getting 
their  share  of  the  profits  the  elevator  men  are  making,  and  are 
not  interested  in  their  employer's  welfare.  So  you  have  had  to 
contend  with  a  trying  situation,  and  it  is  a  fine  testimonial  of  the 
efficiency  of  your  work  that  you  have  been  able  to  accomplish  so 
much  in  this  period  in  the  way  of  reducing  explosions  and  the 
saving  of  life  and  property. 

I  remember  that  at  a  dinner  during  the  war,  the  speaker  said 
that  they  would  not  ask  you  after  the  war  how  you  did  the  thing ; 
they  will  ask,  "Did  you  do  it?"  I  said  to  Mr.  Barnes,  "  Don't 
you  take  that  to  heart ;  they  will  certainly  ask  if  you  fail,  why 
the  work  was  not  done."  But  if  the  work  is  a  success  they  will 
ask  how  you  did  it  and  dig  into  your  record-,  and  the  embarrass- 
ing tiling  will  be  they  will  forget  the  fine  service  that  you  have 
rendered.  And  it  is  particularly  true  in  your  work ;  you  could  not 
go  with  mandatory  authority  to  compel  these  things,  and  so  >ou 
accomplished  it  by  the  persuasive  way;  you  found  out  how  to 
gel  to  them  and  explain  what  you  were  after,  1  have  seen  some 
of  your  minor  demonstrations  and  listened  to  your  lecture - 
seen  interest  that  was  entirely  dormant  thoroughly  awakened.  1 
cannot  see  how  it  was  possible  for  you  to  do  the  work  and 
achieve  the  accomplishments  which  you  have.  And,  really  you 
arc  the  men  that  ought  to  answer  the  question  that  is  now  put 
to  the  Grain  Corporation.  "Why  did  you  fellows  make  money 
out  of  a  Government  operation/1  and  one  answer  is  that  we  never 
expected  to  go  for  two  and  a  half  years  without  a  fire  loss,  when 
was  at  one  time  at  risk  four  hundred  million  dollars  of 
erty. 

146 


You  men  really  belong  to  the  life-savers  of  the  country. 
You  cannot  put  down  the  amount  of  your  work ;  you  cannot 
make  a  complete  compilation  of  it.  You  know  how  many 
addresses  you  made ;  but  you  cannot  compute  the  lives  that  have 
been  saved;  you  cannot  compute  the  property  which  has  been 
preserved ;  that  goes  into  the  eternal  record  and  we  know  nothing 
about  it.  While  you  may  not  belong  to  the  organization  of  actual 
life-savers,  they  only  act  when  life  is  in  peril,  but  yours  is  the 
great  work  of  prevention,  which  after  all  is  the  far  more 
important  life-saving  agency. 

So  this  work  of  prevention  that  you  men  have  been  doing; 
you  cannot  tell  how  great  it  is,  and  you  men  can  take  that  reward, 
which  is  the  greatest  reward:  "  He  that  saveth  life  shall  find  it." 

Mr.  PRICE — I  want  to  thank  you,  Mr.  Moore,  for  those  kind 
remarks ;  they  mean  a  great  deal  to  me,  and  I  know  they  mean  a 
great  deal  to  you  men  in  your  respective  fields  in  the  various 
sections  of  the  country.  You  have  the  assurance  to  carry  back 
with  you,  that  the  work  you  have  been  doing  is  fully  appreciated. 
As  you  know  we  are  going  to  be  compelled  to  discontinue  this 
work  for  lack  of  funds  after  July  1st.  This  gives  you  double 
assurance  in  your  future  work,  which  will  probably  be  somewhat 
different  from  the  work  you  have  been  doing  during  the  period 
of  the  war  and  since  the  armistice;  and  the  service  rendered  has 
been  of  a  nature,  as  Mr.  Moore  said,  that  cannot  be  computed; 
work,  the  results  of  which  were  far-reaching,  and  lias  probably 
assisted  in  the  adoption  of  additional  precautionary  measures.  I 
feel,  Mr.  Moore,  that  we  again  want  to  thank  you  for  your  very 
kind  remarks  concerning  us  and  the  work  we  have  done,  and 
it  has  been  a  very  great  source  of  gratification  to  hear  it  from 
you.  We  have  been  able  to  help  in  the  protection  and  hnpn 
nient  of  conditions  in  industrial  plants,  but  we  would  not  have 
beeii  able  to  do  bo  without  the  strong  co-operation  and  far- 
sighted  polieie>  on  the  part  of  the  (.rain  Corporation  officials. 

We  will  now  hear  from  Dr.  Duvel  regarding  the  interesl 
of  the  Grain  Corporation  in  Dust  Explosion  Prevention.  I 
feel  that  Dr.  Duvel  is  the  man  who  was  very  largely  instru- 
mental iii  steering  us  on  the  right  track  by  getting  us  in 
contact  with  the  (.rain   (  orporation   in   this   work. 


147 


INTEREST     OF     GRAIN     CORPORATION     IN     DUST 
EXPLOSION  PREVENTION. 

By  Dr.  J.  W.  T.  Duvel. 

Dr.  DUVEL — I  had  in  mind,  in  presenting  this  matter 
to  you  this  morning,  to  refer  briefly  to  what  this  work  has 
meant  to  the  Grain  Corporation.  Fortunately  much  of  this  has 
already  been  covered  by  Mr.  Moore  at  the  banquet  the  other 
night,  by  Mr.  Barnes  in  his  remarks  at  our  meeting  yesterday, 
and  by  Mr.  Moore  again  this  morning.  I  am  very  glad  it  has 
turned  out  that  way,  particularly  for  the  benefit  of  you  men, 
because  I  know  you  appreciate  hearing  from  Mr.  Barnes  and 
from  Mr.  Moore  themselves  as  to  the  interest  they  had  in  this 
work.  I  suspect  a  great  many  of  you  men  while  in  the  field 
have  felt  that  the  Grain  Corporation  was  only  indirectly  inter- 
ested in  this  work,  and  that  this  thought  applied  particularly 
to  Mr.  Barnes  and  to  Mr.  Moore,  but  I  want  to  assure  you,  if 
such  assurance  is  necessary  after  what  you  have  heard  them 
say,  that  they  have  taken  a  broader  view  of  this  question. 
Both  Mr.  Barnes  and  Mr.  Moore  have  been  intensely  inter- 
ested in  every  phase  of  this  work.  We  got  into  this  work 
primarily,  of  course,  to  protect  our  large  stocks.  As  Mr. 
Moore  said  this  morning,  at  one  time  we  had  nearly  half  a 
billion  dollars  worth  of  property  at  stake,  without  one  dollar 
of  insurance.  But  in  addition  to  that,  Mr.  Barnes  has  been 
interested  in  the  educational  campaign,  authorizing  the  trip 
that  Dr.  Brown  has  made,  which  was  largerly  educational, 
going  into  sections  where  we  had  no  grain  stored,  and  also 
the  work  you  have  been  doing  in  the  last  two  or  three  weeks, 
going  into  country  elevators,  into  small  plants  in  different  sec- 
tions, following  up  the  same  line  of  work  that  you  carried  on 
a  year  ago  and  two  years  ago.  1  am  frank  to  say  that  in  m\ 
own  mind  there  was  some  doubt  in  the  beginning  whether  Mr. 
Barnes  would  care  to  go  that  far  for  fear  there  might  be  sonic 
criticism  of  our  extending  our  authority  to  that  extent,  but 
when  it  was  presented  to  Mr.  Barnes  by  Mr.  Price  and  myself, 
he  immediately  said  that  we  could  go  ahead  with  this  work, 
and  while  our  own  stocks  were  getting  smaller,  that  he  wanted 

to  carry  this  message  home  i"  the  people,  to  do  what  good  was 
possible  at  the  present  time,  but   more  particularly   for  the 

future. 

We  had  intended  holding  this  conference  as  more  or  less 

of   a    conclusion    to   our    work,    as    you    know    being   originally 

148 


scheduled  early  in  May  but  after  I  found  that  the  banquet 
in  honor  of  Mr.  Barnes  was  to  be  on  the  22d,  I  immediately 
took  steps  to  have  it  moved  up  so  that  you  men  could  come 
in  and  enjoy  it  as  an  incidental  feature  of  this  conference. 

At  the  present  time  our  stocks  of  wheat  are  very  low.  We 
have  something-  in  the  neighborhood  of  twelve  million 
bushels,  practically  all  of  which  has  been  sold,  there  being 
four  million  of  that  amount  due  mills,  and  eight  million  due 
for  export,  leaving  a  balance  net  surplus  unsold  of  only 
433,798  bushels  as  of  April  16.  Of  these  twelve  million  bushels 
we  have,  most  of  it  is  at  Buffalo,  Minneapolis  and  Chicago, 
and  we  will  keep  watch  on  that  ifntil  it  is  delivered  or  finally 
disposed  of. 

I  think  one  of  the  most  interesting  things  you  will  be  able 
to  take  away  with  you,  is  a  point  that  Mr.  Moore  indicated 
this  morning,  namely,  the  amount  of  insurance,  or  rather  the 
risk  assumed  by  the  Grain  Corporation.  We  had  this  data 
brought  together  a  short  time  ago.  From  October  1,  1917  to 
July  1,  1919,  the  average  value  of  the  weekly  holdings  at  all 
points  was  approximately  one  hundred  million  dollars; 
Buffalo  running  just  under  fifteen  million,  Chicago  just  under 
seventeen  million,  Duluth  just  under  fourteen  million,  and 
Minneapolis  a  little  over  fifteen  million  dollars,  and  the  bal- 
ance being  made  up  with  the  markets  carrying  a  smaller 
quantity  of  stock.  Taking  these  holdings  in  the  various 
markets  at  the  average  rate  of  insurance  applied  to  most  of 
the  houses  for  that  pcri<»d,  we  find  if  we  had  paid  insurance, 
instead  of  carrying  our  own  risk,  that  the  premiums  during 
that  period  would  have  been  $1,961,500.  That  is  from  (  October 
1.  1917.  to  July  1,  1919,  covering  a  period  of  twenty-one 
months.  Adding  that  to  the  amount  we  have  carried  this  year, 
would  mean  a  total  in  round  numbers  of  three  million  dollars 
that  we  would  have  paid  in  premiums  on  the  grain  in  the 
elevators.  The  Grain  Corporation  carried  its  own  insurance, 
and  that  is  the  reason,  of  course,  we  were  anxious  to  see  that 
proper    precautions    were    taken    at    all    points    during    the    entire 

life  of  the  drain  Corporation.    We  have  not  had  a  single  I 

by   tire.     The  only  loss   we  have  had   is  in  connection  with  the 

Kansas  City  explosion,  where  our  grain  loss,  in  salvaging  the 

-rain,  it"  1  remeinher  the  figures  correctly,  was  $25,000.  We 
had.  of  course,  some  losses  both  on  the  Lakes  and  the  Atlantic. 
hut   that    is   outside   of   our  dust   explosion    field,  and    in   most 


L49 


.  in   fact.   I   think  all  cast-,  grain  moving  on  the  Lakes 
and  going  for  export  was  insured  and  fully  protected. 

The  following-  tabulation  will  show  in  detail  the  average 
value  of  our  holdings,  average  rate  of  insurance,  and  the  risk 
assumed,  or  rather  the  premiums  which  the  Grain  Corporation 
would  have  paid  if  insurance  had  been  covered  in  the  regular 
way : 


Average  Value 

Terminal.  in  Store.        Rate. 

Baltimore    $2,281,865 

Buffalo  14,856,728 

Chicago    16,723,000 

Duluth    13,884,380 

Galveston 2,159,702 

Kansas  City   9,482,892 

Minneapolis    15,121,329 

New  Orleans   ....  4,027,819 

Omaha    3,829,324 

Philadelphia   1,743.730 

Portland    7,585,610 

St.  Louis  2,249,478 

San    Francisco....  809,300 

New  York 2,486,637 


Remark. 

Estimate  

Average   

Average  

Average  

Average    

Average    

Estimate  same  as 
Chicago    

Included  in  Ele- 
vator Rates. 

Average   

Average   

Estimate  

Estimate  same  as 
Chicago    

Average    

Average   


Premium. 


$0.30 
1.40 
1.31 
1.71 
1.73 
1.40 

None 

1.68 
2.00 
1.00 
1.40 

1.13 
.94 


$18,001) 
78,000 

409.000 

316,000 

04.500 
287,000 

370,000 


112,800 
61,000 

133.000 

55,300 
16.000 

40.0(H) 


$1,961,500 


Notes. — 

1.  Period  covered— October  1,  1917,  to  July  1.  1919—21  months. 

2.  Values  were  based  on  the  average  quantities  in  store,  week  by  week, 
over  the  entire  period  as  reported  to  the  Grain  Corporation  on  dailj 
terminal  elevator  reports,  calculated  on  the  basis  of   No.  2  wheat. 

3.  Insurance  rates  were  arrived  at  by  taking  the  average  of  -dl 
elevators  in  each  terminal  for  which  data  were  available,  (This  covered 
practically  all  house* 


There  is  another  point  thai  has  been  very  interesting  to  me  in 
connection  with  this  work,  and  that  is  a  statement  I  saw  a  few 
days  ago,  from  report  of  the  National  Safetj  Council,  giving  the 
number  of  persons  killed  by  accident  in  the  United  States  last 
year  as  80,000.  Of  this  number  we  had  7$  who  lost  their  lives 
as  a  result  of  du9t  explosions.  Seventy-eight,  as  compared  with 
eighty  thousand,  of  course,  is  a  small  number,  yet  in  a  city  like 

\ew  York,  every  day  that  you  pick  up  a  paper  you  see  reports  <>| 

a  number  of  people  killed  by  accident,  and  it  seems  to  me,  when 
we  take  those  figures  into  consideration,  that  we  realize-  more 
fully  what  tin's  dust  explosion  work  really  means;  and  as  Mr. 
Moon-  has  said,  the  number  of  Kves  that  have  been  saved  by  pre- 
ventive measures  is  something  we  shall  never  know. 

150 


I  do  not  know  that  it  is  necessary  for  me  to  take  up  any  more 
time.  I  wish  to  say,  however,  it  has  been  a  pleasure  for  me  to 
have  been  associated  with  you  men  in  this  work.  I  have  pur- 
posely kept  in  the  background  as  much  as  possible  because  1  was 
in  hope  that  you  would  be  able  to  go  ahead  with  the  work  in  the 
United  States  Department  of  Agriculture  next  year,  and  I  desired 
you  to  have  the  credit  you  so  fully  merit.  It  is  a  great  disappoint- 
ment to  me  that  you  will  not  be  able  to  do  it,  but  I  hope  that  some 
time  in  the  near  future  Congress  will  see  the  wisdom  of  continu- 
ing this  work  in  the  Department.  As  you  men  leave  this  work. 
I  am  sure  it  will  be  with  the  satisfaction  that  you  have  rendered 
excellent  service,  even  though  you  cannot  point  directly  to  lives 
you  have  saved.  Again,  I  wish  to  repeat  it  has  been  a  pleasure 
to  know  and  to  work  with  you.  If  anything  comes  up  where  I 
can  help  you  in  your  new  work  along  similar  lines,  or  any  new 
lines  that  you  may  undertake,  I  am  sure  it  will  be  a  pleasure  for 
me  to  do  it. 

SUMMARY  OF  DUST  EXPL(  »SIONAND  FIRE  PREVEN- 
TION  CAMPAIGN. 

By  D.  J.  Price. 

Origin  of  Campaign. 

The  Grain  Dust  Explosion  Prevention  Campaign  was  inaugu- 
rated October  1917,  by  the  Department  of  Agriculture.  The 
disastrous  losses  as  a  result  of  explosions  and  fires  in  mills  and 
elevators  emphasized  the  importance  of  taking  all  precautions  to 
conserve  our  food  supplies  in  connection  with  our  war  activities. 
'I  be  investigation  of  a  number  of  these  explosions  very  clearly 
indicated  that  the  employees  and  officials  were  not  fully 
acquainted  with  the  causes  under  which  these  explosions  could 
originate  and  methods  that  might  be  followed  for  their  pre- 
vention.     The  campaign   was  conducted  in  co-operation   with  the 

Food  Administration  and  other  conservation  commissions  until 
June  30,  I'd'',  when  the  war  emergency  appropriation  terminated. 

Grain  Corporation  Campaign. 

At  the  termination  of  the  war  emergency  campaign  provision 
was  made-  by  the  U.  S.  Grain  Corporation  through  Mr.  Julius  II. 
Barnes,  President,  to  maintain  sufficient  organization  to  protect 
tin-  Government's  wheat  and  Hour  stocks  in  storage  from  explo- 
sion and  tire  hazards.  'Ibis  work  ha-  bun  carried  on  actively 
during  the  past  year  and  special  attention  ha>>  been  given  to  the 

151 


plants  in  which  these  stocks  were  handled  or  stored.  Frequent 
inspections  have  been  made  from  time  to  time  and  assistance 
rendered  in  the  removal  of  dangerous  conditions  that  might  lead 
to  explosions  and  fires. 

Educational  Work. 

In  addition  to  the  visits  to  the  plants  for  the  removal  of  these 
dangerous  conditions  special  educational  work  was  conducted 
among  the  employees  and  officials.  The  pledge  cards  used  dur- 
ing the  war  period  by  which  the  moral  support  of  the  men  was 
enlisted  gave  very  valuable  results.  The  work  was  presented  to 
the  men  by  means  of  specially  prepared  photographs  showing 
the  damage  to  mills  and  elevators  as  results  of  dust  explosions 
and  also  preventative  methods  that  should  be  followed.  Demon- 
strations of  dust  explosions  were  produced  in  order  to  show  the 
men  the  simple  manner  in  which  these  explosions  could  occur. 
Every  effort  was  made  to  fully  acquaint  the  workmen  with  the 
information  that  the  Department  had  acquired  and  to  give  them 
the  full  knowledge  of  the  dust  explosion  and  fire  hazard. 

Literature. 

In  this  campaign  special  literature  prepared  in  simple  readable 
language  was  provided.  During  the  war  period  a  specially 
designed  wall  poster  entitled  "  Save  Lives,  Save  Food  and  Save 
Property"  was  distributed  throughout  the  mills  and  elevators. 
This  poster  contained  a  list  of  the  simple  precautions  that  might  be 
followed  to  prevent  these  occurrences.  The  circular  entitled 
"  Prevent  Dust  Explosions  and  Fires,"  and  also  the  small  folder 
known  as  the  "  Capitol  "  folder  were  prepared  for  distribution 
among  the  employees.  This  circular  and  folder  contained  a  num- 
ber of  lessons  that  impressed  the  workmen. 

During  the  Grain  Corporation  Campaign  a  specially  colored 
wall  poster  showing  the  results  of  carelessness  and  the  benefit 
of  cleanliness  was  used  with  good  results.  A  circular  entitled 
"Just  a  Word  About  Grain  Dust  Explosions"  containing  an 
account  of  8  explosions  due  to  causes  controlled  by  the  workmen 
together  with  12  rules  for  safety  was  issued.  The  small  folder 
entitled  "4  Reasons  Why  You  Should  he  Careful"  was  well 
received  bv  the  workmen  and  a  wide  distribution  was  given. 

The  demand  from  the  milling  and  grain  companies,  insurance 
people,   conservation   associations   and   other   interested   parties 

has  shown  the  value  of  this  literature. 

152 


Co-operation. 

In  the  campaign  active  co-operation  has  been  given  by  the 
milling  and  grain  trade,  insurance  and  conservation  commissions, 
fire  prevention  agencies  and  state  officials.  The  presentation  of 
the  work  throughout  the  country  has  been  wonderfully  benefited 
by  this  co-operation  which  has  endorsed  the  efforts  of  the  Federal 
Government  and  made  it  possible  to  apply  the  preventive 
methods  in  a  practical  manner.  This  opportunity  is  taken  to 
express  appreciation  for  the  co-operation  and  assistance  rendered 
by  these  agencies.  What  success  may  have  attended  this 
campaign  is  due  to  a  large  degree  to  the  splendid  co-operation 
given  the  Government  in  this  work. 

Dust  Explosion  Meetings. 

In  addition  to  the  group  meetings  held  at  the  plants  to  acquaint 
the  workmen  with  the  dust  explosion  fire  work,  a  series  of  meet- 
ings were  held  in  the  larger  cities  throughout  the  country.  These 
meetings  were  attended  by  members  of  the  grain  trade  and  other 
interested  parties  and  specially  prepared  motion  picture  reels  were 
used.  These  films  showed  the  results  of  both  laboratory  and  large 
scale  explosion  experiments,  together  with  views  of  large  mills 
and  elevators  damaged  by  explosions  and  fires  accompanied  by 
large  loss  of  life  and  foodstuffs.  In  addition  to  the  meetings  in 
the  United  States,  at  the  Request  of  the  Dominion  Fire  Commis- 
sioner a  meeting  was  held  at  Fort  William,  Ontario.  Interest  in 
the  work  was  awakened  in  Canada  as  a  result  «>t"  the  Port 
Colborne  explosion  and  the  meeting  was  well  attended. 

CONVENTIOJ 

in  addition  to  the  public  meetings  held  in  the  larger  grain 
centers  throughout  the  country  the  work  was  presented  at  a 
number  of  conventions  in  the  United  States.  Among  the>e  are 
Included  the  National  Fire  Protection  Association,  National 
Firemen's  Association,  Railway  Fire  Prevention  Association, 
Illinois  State  Firemen's  Association,  Iowa  Grain  Dealers  and 
conventions  of  several  millers'  associations.  At  these  conventions 
the  motion  pictures  were  used  and  demonstrations  oi  dust  ex 
plosions  produced  by  means  of  a  miniature  elevator,  and  also  by 
sifting  the  dnst  through  a  cheese  cloth  onto  a  burning  match. 
These  demonstrations  were  similar  to  those  given  at  the  meet 
ings  lu-ld  in  the  larger  grain  centers  and  at  the  various  grain 
plants. 

153 


Method  of  Report  of  Inspection. 

The  results  of  the  inspection  of  the  elevators  were  reported 
both  to  the  district  and  to  the  Washington  office.  The  following 
method  of  classification  was  used : 

Equipment  Maintenance 

A.  Modern,  first-class,  up-to-date  appliances.               A.     Good. 

B.  Fair,  not  new.  B.     Fair. 
(  .     ( )ld  and  not     *oresentitive.  C.     Poor. 

A  well  constructed  plant,  with  modern  mechanical  appliances, 
would  be  given  "A"  for  equipment.  If  precautionary  measures 
were  being  carried  out,  and  the  explosion  hazard  recognized,  the 
plant  received  "A"  for  maintenance.  The  classification  for  such 
a  plant  would  then  be  "  AA."  If  the  maintenance  was  not  up  to 
the  standard  and  the  dust  conditions  looked  after  in  only  a 
"  fair  "  manner,  the  classification  would  be  "  AB."  If  the  plant 
was  well  equipped,  but  found  in  a  dirty,  dusty,  or  poor  condition, 
it  would  receive  a  grade  of  "AC."  In  many  cases,  however, 
equipment  which  was  not  strictly  modern,  but  was  rendering  satis- 
factory service  was  put  in  the  "B"  class  to  distinguish  it  from 
that  of  newer  type  or  design.  If  the  plant  was  well  maintained  it 
would  be  classed  as  "  BA,"  while  "  BB  "  and  "  BC  "  represented 
the  intermediate  and  poor  classes,  respectively.  Old  type  plants, 
in  which  the  equipment  had  been  installed  for  some  time  fill  in 
the  "C"  class.  When  it  was  well  maintained  and  particular 
attention  was  paid  to  the  removal  of  the  dust  conditions,  the 
plant  would  be  placed  in  the  "  CA  "  class.  Similarly,  "  CB  " 
and  "  CC  "  represented  the  other  grades  of  upkeep  and  main- 
tenance. 

These  reports  also  were  sent  immediately  to  district  head- 
quarters and  then  to  Washington,  so  the  officials  in  charge  could 
at  all  times  keep  in  close  contact  with  the  general  conditions 
of  the  mills  and  elevators  throughout  the  country.  By  com- 
parison with  previous  reports,  it  was  possible  to  determine 
whether  or  not  the  condition  of  the  elevator  was  improving  and 

whether   the   precautionary   measures   previously    recommended 
had  been  adopted. 

Improvement  in  Condition-  of  Plants. 

That    conditions    in    the    mills    and    elevators    inspected    were 

materially  improved  as  a  result  of  the  recommendations  made 
to   tin-   officials    in   charge   ia   evident    from    the   report   turned    in 

154 


by  the  field  men.     The  following  table  gives  a  few  typical  cases 
of  the  results  of  this  phase  of  the  work : 


Elevator              Visit  Date                                              Grade 

1  1  September  4,  1919 AC 

2  September  26,  1919 AB 

3  February  18,  1920 \A 

1  September  23,  1919 U 

2  November  29,  1919 VB 

3  March  5,  1920 \A 

1  November  26,  1919 BC 

2  March  1,  1920 BB 

3  March  20,  1920 BA 

1  September  11,  1919 CC 

2  October  17,  1919 CB 

3  February  4,   1920 CA 

1  August  19,  1919 \  A 

2  December  17,  1919 \  A 

3  January  28,   1920 \A 

4  April  13,  1920 \\ 


(Middle  West) 

2 
(East) 

3 

(East) 

4 
(West) 

5 
(East) 


Elevators  1  and  2,  although  well  constructed  and  equipped 
with  modern  machinery,  were  poorly  maintained  at  the  time  of 
the  tir.st  inspection.  As  a  result  of  following  the  recommenda 
tions  made  by  the  inspector,  conditions  were  so  improved  that 
when  the  lasl  inspection  was  made  the  plants  received  the  grade 
of  "  AA." 

Although  elevator  3  remained  in  class  "B"  (medium)  for 
equipment,  it  improved  sufficiently  in  condition  to  rise  from  "C 
to  "  A  "  in  maintenance. 

Elevator  4  was  poorly  equipped  and  very  poorly  maintained. 
showing  evidence  of  but  little  precaution  against  fires  and  ex 
plosions.     The  information   received  by  the  officials,  however, 
enabled  them  to  bring  their  grade  up  to  "  B,M  and  finally,  after 

they  had  adopted  additional  methods  of  dust  explosion  and  li  i  e 
prevention,  to  "  A."  'The  equipment  in  this  plant  was  not  im- 
proved, remaining  in  the  "  C  "  grade. 

Elevator  5,  modern  in  construction  and  equipment,  was  found 

at  the,  time  of  each  visit  tO  be  in  an  excellent  condition  and  pro 

vided  with  every  device  for  minimizing  the  dangers  from  dust 
explosions. 

As  this  summary  is  representative  of  the  large  number  of 

155 


reports  received  from  all  over  the  country,  it  may  be  concluded 
that  the  recommendations  made  in  this  campaign  brought  about 
an  improvement  in  conditions  and  a  decrease  in  dangers  from 
explosion  and  fire  in  the  mills  and  elevators  of  the  United  States. 

CO-OPERATION    OF   ZONE   AGENTS. 

As  a  result  of  a  disastrous  explosion  in  a  Southwestern  eleva- 
tor, a  definite  plan  of  co-operation  with  the  zone  agents  of  the 
Grain  Corporation  was  provided.  When  the  plants  were  found 
to  be  in  a  dangerous  condition  a  report  was  immediately  made  to 
the  second  Vice-President  of  the  district  with  the  result  that  steps 
were  at  once  taken  to  remove  this  condition.  In  many  instances 
it  was  felt  that  explosions  were  prevented  by  this  action  when 
prompt  steps  were  taken  to  remove  the  hazard  that  had  been 
found  by  the  engineer  upon  a  visit  to  the  elevator  or  mill.  It  was 
a  splendid  example  of  how  results  could  be  obtained  by  calling  the 
matter  to  the  attention  of  the  officials  in  charge. 

Electrical  Developments. 

Investigations  of  explosions  during  the  period  of  the  cam- 
paign indicated  the  possibility  of  dust  ignition  by  the  breaking 
of  incandescent  lamp  bulbs.  The  matter  was  taken  up  with  the 
manufacturers  of  lamps  and  a  co-operative  plan  provided.  At 
present  the  National  Lamp  Works  of  Cleveland,  Ohio,  the  West- 
inghouse  Company  of  Bloomfield,  N.  J.,  and  the  Edison  Lamp 
Works  of  Harrison,  N.  J.,  are  working  on  the  problem.  It  is 
hoped  that  as  a  result  of  this  combined  effort  that  safety  equip- 
ments will  be  provided  and  safe  practices  can  be  developed.  This 
is  an  important  matter  and  will  be  given  thorough  consideration. 
In  the  experimental  tests  already  conducted  explosions  have  been 
readily  produced  by  the  breaking  of  the  bulb  in  dust  clouds.  An 
effort  is  now  being  made  to  determine  the  effect  of  dust  settling 
on  these  bulbs  and  the  relation  to  explosion  and  fire.  Several 
conferences  have  been  held  with  the  representative  lamp  com- 
panies and  a  definite  program  of  research  investigational  work 
has  been  outlined. 

Further  Co  opera  noN. 

Following  the  investigation  of  the  explosion  in  the  aluminum 
goods  manufacturing  plant  in  Wisconsin  a  conference  was  held 
at  Madison  with  representative  commissions.  Special  attention 
will  be  given  to  the  elimination  of  dangerous  dust  hazards  in  thai 

siaic  with  the  possibility  of  a  prevention  code  being  provided. 

156 


Since  the  explosion  at  Port  Colborne  we  have  co-operated  in 
an  active  manner  with  the  Canadian  Government  officials,  insur- 
ance commissions  and  other  fire  prevention  agencies  in  the 
Dominion.  It  is  hoped  that  this  co-operation  will  continue  and 
lead  to  a  combined  effort  on  the  part  of  both  governments  to 
conduct  further  investigational  work. 

Threshing  Machine  Explosion  Prevention. 

During  the  past  year  the  devices  developed  by  the  Depart- 
ment for  the  prevention  of  threshing  machine  explosions  have 
been  recognized  by  the  insurance  interests  in  the  Northwest.  Ai 
a  recent  conference  in  Seattle  with  representatives  of  the  insur- 
ance companies  favorable  consideration  was  given  looking  fur- 
ward  to  a  reduction  in  the  existing  rates  in  cases  where  the  pre- 
ventive equipment  is  used  on  threshing  machines. 

Lack  of  Appropriation. 

The  Dust  Explosion  Prevention  Campaign  will  terminate  to 
a  large  extent  June  1.  It  may  be  necessary  to  maintain  part  of 
the  organization  to  protect  the  Grain  Corporation  stocks  still 
remaining  in  the  elevators  until  about  July  1. 

Unfortunately,  the  present  Congress  has  made  no  provision  in 
the  appropriation  for  the  Department  of  Agriculture  for  the  Dust 
Explosion  Work.  The  war  emergency  appropriation  terminated 
July  30,  1919,  and  since  that  time  the  organization  has  been 
financed  by  the  U.  S.  Grain  Corporation.  '1  he  Secretary  of  Agri- 
culture submitted  to  the  present  Congress  an  estimate  of  $100,000 
for  the  investigation  and  prevention  of  dust  explosions  and  fires. 
This  included  three  lines  of  work:  First,  explosions  in  mills  and 
elevators;  second,  threshing  machines,  and  third,  cotton  gins  and, 
included  the  lines  of  work  which  the  department  would  like  to 
carry  on. 

The  bill  as  reported  by  the  Agricultural  committee  of  the 
House  contained  an  item  of  $25,000  for  the  dust  explosion  work. 
A  point  of  order  was  made  against  the  item  on  the  floor  of  the 
House  on  tlu-  ground  that  it  was  new  legislation,  which  was  sus- 
tained  by   the  chair,    with   the   result   that    the   item   was   stricken 

from  the  hill  before  it  passed  tlu-  I  [ouse. 

I  he  Secretary  recommended  to  the  Agricultural  committee  of 
the  Srnau-  that  the  item  hi-  reinstated  in  the  hill  before  being 
reported  to  the  Senate.    Unfortunately  for  some  reason  this  v 
nut  done  and  the  hill  as  Introduced  and  passed  by  the  Senate 

contains  no  provision  for  the  work. 

157 


This  is  to  be  regretted  because  the  Department  will  not  be 
able  to  carry  on  the  investigations  planned  pertaining  to  the  Dust 
Explosion  Work.  The  organization  must  be  disbanded  and  the 
work  cannot  be  taken  up  in  an  active  manner  until  the  necessary 
appropriations  are  made.  The  Department  feels  that  owing  to 
the  very  close  relation  to  the  saving  of  life,  food  and  property 
that  provision  should  be  made  for  the  continuation  of  the  work. 

Results  of  Campaign. 

The  Grain  Corporation  has  handled  practically  the  grain 
crop  for  approximately  three  seasons.-  The  stocks  have  averaged 
about  $100,000,000  in  value  and  have  reached  in  some  instances 
$500,000,000.  With  the  exception  of  a  slight  loss  as  the  result 
of  an  explosion  in  a  Southwestern  elevator  the  entire  Grain 
Corporation  stocks  have  been  handled  without  any  extensive  dust 
explosion  and  fire  losses.  This  is  a  very  significant  fact  when  we 
consider  that  disastrous  dust  explosions  have  occurred  in  other 
industries.  During  the  period  of  the  last  twelve  months,  at  least 
seven  of  these  explosions  have  occurred  involving  loss  of  life 
and  property.  The  total  life  loss  will  exceed  eighty  and  the 
property  damage  over  $7,000,000. 

The  results  obtained  in  the  campaign  indicate  that  through 
the  co-operation  with  the  officers  and  workmen  at  the  plants  and 
the  various  fire  prevention  agencies,  these  dust  explosions  and 
fire  losses  can  be  prevented. 

Investigation  of  these  recent  explosions,  however,  has 
developed  new  causes  and  necessity  for  additional  lines  oi 
research  work.  This  is  included  in  the  program  provided  by  the 
Department  of  Agriculture  which  cannot  be  taken  up  until  Con- 
gress makes  the  necessary  provision.  It  is  felt  that  this  investiga- 
tional work  must  be  continued  and  effective  methods  of  preven- 
tion developed  before  we  can  reduce  the  loss  to  life,  foodstuffs 
and  property  in  our  large  industrial  plant-. 

Appreciation  of  Work. 

We  fully  appreciate  the  assistance  that  has  been  rendered  by 
the   men   engaged    in   the   campaign   and   the    faithful    manner   in 

which  they  have  performed  their  work.  It  has  made  it  possible 
for  the  Government  to  bring  to  the  attention  of  the  men  in  the 
plants  the  extent  to  which  they  control  these  explosions  and  fires 

and  to  see  that  the  necessary  BtepS  are  taken   for  their  prevention. 

1 1  is  a  source  of  very  great  gratification  to  close  the  campaign 

and   feel  that   SOttie  definite  results  have  been  accomplished  which 

158 


arc  fully  appreciated  by  the  Grain  Corporation,  and  milling  and 
grain  trade  throughout  the  country.  It  is  hoped  that  provision 
will  be  made  in  a  very  short  time  for  the  proper  continuation  of 
the  investigational  work.  In  closing  this  summary  we  desire  to 
express  our  sincere  appreciation  of  the  interest  shown  by  Mr. 
Barnes  in  the  work,  and  the  endorsement  and  recognition  given 
by  the  entire  Grain  Corporation  organization.  It  indicates  the 
important  relation  of  the  dust  explosion  prevention  to  the 
country,  and  the  necessity  for  its  continuation  until  the  dangers 
surrounding  the  causes  are  fully  understood,  and  effective 
methods  of  prevention  can  be  developed. 


159 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  9688 


DUST-ffeEE 

Mills  and  Elevators 

aw  Explosion- 
Proof 


Carelessness 


a  lighted  match 
dusty  machinery 
an  uncovered  candle 

or  lantern 
friction  in  machinery 


Cleanliness 


means  nothinO  to 

explode 
protects  worKmens'  lives 
saves  property 
saves  food 


ILS.Grain  Corporation- 

U.S.  Department  of  Agriculture 

Ibr  further  Information  about  grain  duit  exptorioru  write  to  the 
Bureau  of  Chemlrtry,  —  U .  S.  Department  of  Agriculture. 


